“The show makes the star, not the other way around.” It’s an old television-industry adage, one repeated nearly as often as it’s ignored. No matter the shininess or popularity of a given celebrity, audiences have proved happy to shun them if the TV show constructed around them is lacking. Unlike the movie industry, which ranks actors’ influence on their ability to deliver big opening weekends at the box office, TV demands a more lasting commitment. And that, in turn, demands more than a familiar name. Anybody will watch something once. The trick in television is getting them to watch again and again.

And no matter how much starry-eyed executives would love to deny it, the pulling of said trick demands a lot more than shelling out cash and mocking up a poster. There needs to be a compelling reason to watch other than the name at the top of the call sheet. Just because everyone loved Kramer doesn’t mean they wanted to watch The Michael Richards Show. Hell, just because everyone loved Raymond still didn’t do much to save Men of a Certain Age. Already this fall, viewers have wisely rejected Ironside and We Are Men. The failure of those two lousy shows wasn’t a referendum on the relative popularity of Blair Underwood and Tony Shalhoub, well-liked and dependable performers who will be employed for as long as they want to be. They were referendums on their chosen comeback vehicles. And the verdict was swift and definitive.

The jury is still out on the fall’s two biggest star-driven projects — although they’re trending in opposite directions. The Crazy Ones on CBS marks Robin Williams’s return to the medium that birthed him, from a giant egg, over three decades ago. Created by veteran drama-slinger David E. Kelley, the show is set in a Chicago advertising agency over which Williams — as newly sober mad man Simon Roberts — presides with a predictably manic glee. Thus far, the craziest thing about the series is the ratings: After debuting with an eye-popping 15.5 million viewers, the show has settled into a weekly average of slightly more than half that. (Yes, it’s sandwiched between megahits The Big Bang Theory and Two and a Half Men, but no bread is good enough to get ratings like that without something marginally appealing in the middle.) By contrast, Michael J. Fox’s return to NBC’s Thursdays, the network and night where he first made his name, has been less welcoming. He has brought the family with him — the show is basically a 21st-century version of the Keatons with Fox as the father — but has seemingly lost all the ties: The most recent episode garnered an anemic 2.5 million viewers, with less than half that number in the coveted 18-to-49-year-old demographic. Thanks to the overzealous bidding strategy of a desperate network, The Michael J. Fox Show is guaranteed a full season. Without that promise, the show’s putrid ratings would likely have it fading from the schedule faster than a McFly sibling.

When big stars return to television, it’s generally more about their needs than those of the network — let alone those of the viewers. Sixteen years from winning an Oscar and recently removed from a trip to rehab and major heart surgery, Williams’s work options appeared limited to fringey passion projects and cartoons both literal and otherwise. That he should seek solace in the forgiving arms of television is perfectly logical. What’s odd about The Crazy Ones is that it chooses to highlight the version of Robin Williams that film audiences had spent the better part of a decade rejecting. This is Williams in full hyperactive frenzy. The flop sweat flying off of him? Pure schmaltz. Rather than rein in its rampaging star, The Crazy Ones goes out of its way to encourage him.

Entire episodes are built around wacky accents, plots screech to a halt to accommodate musty bits and bug-eyed vamping. After indulging a creaky Three Stooges imitation, Sarah Michelle Gellar — playing Sydney, Williams’s harried daughter and partner in the firm — says, “You know there’s something truly wrong with you, right?” But everyone is aware it’s meant to be a compliment. This isn’t an advertising agency, it’s San Francisco and Williams is Batkid. The Lewis, Roberts & Roberts offices are dominated by a giant caricature of his face but it’s an unnecessary addition; the real thing is plenty broad enough.

There’s so little oxygen left on set it’s a wonder the rest of the cast hasn’t asphyxiated. I’m particularly concerned for James Wolk, an actor whose effervescent charm feels dangerously close to bubbling away into nothingness. Wolk, so promising on Lone Star and Mad Men (he was international man of mystery — and shorts! — Bob Benson), plays Zach, a chipper himbo who goes bit-for-bit with Williams in pursuit of a cross-generational bromance. So far he’s traded meat innuendos with Kelly Clarkson, adopted a high-plantation accent with Williams, and posed in jean shorts on the hood of a car. Yes, he’s plenty winning. But at what cost? The Crazy Ones is neatly divided between the pampered man-children who act up and the flustered women who find them essentially hilarious. (Hamish Linklater, a saturnine presence on The Newsroom last season, plays Andrew, a stick-in-the-mud who is resolutely stuck in the middle.) Amanda Setton, late of The Mindy Project, at least has the excuse of not yet having a character to play. (She’s ditzy … but maybe also a stalker?) The real downer is seeing Gellar, so tough on Buffy the Vampire Slayer, reduced to stamping her feet and blushing about sex. Why do the boys get to have all the fun?

Though the show has a worrying tendency toward humor that is both lazy (gay people love antiquing!) and easy (old people think young people are hippies!), recent episodes have lurched toward more promising terrain. Having Brad Garrett (as the firm’s stuffy money man) and Ed Asner (as an aging commercial legend) around has helped, as has the time spent on Simon’s past as a blackout drunk. Contrary to mountains of evidence, Williams is a subtle and affecting actor when he wants to be, and he approaches these moments with real heart. Unfortunately, whatever genuine emotion he churns up is soon washed away in overwhelming tsunamis of forced bonhomie. We love it when actors entertain us, yet there’s nothing quite as off-putting as the sight of actors busily entertaining themselves. I’ve never seen a show so convinced of its own delightfulness, so desperate to share its own relentless, unearned good cheer. As if extended montages of the cast mincing around in drag and kangaroo suits weren’t enough, every episode ends with extended blooper reels in which the stars and their celebrity guests collapse into hysterics. The effect is like watching videos of someone else’s vacation. It’s too bad laughter isn’t transitive, like yawning. If it were, The Crazy Ones would probably have me doing a lot more of the former than the latter.

The Michael J. Fox Show isn’t nearly so noxious. In fact, it’s hard to have a particularly strong reaction at all to a show that seems to exist solely as a result of Fox’s desire to get back in the game. The actor plays Mike Henry, a beloved New York City newsman recently returned to work after many years spent adjusting to a new reality with Parkinson’s disease. Because this is a proudly throwback sitcom on a network scrabbling to desperately turn back the clock to a more successful era, Mike is beset by high jinks at home and at the office, all of which are handled with the actor’s trademark blend of winsome good humor and smiling, put-upon snark. Never before has a series been so accurately named (and yes, I’m including Fox’s ill-fated The Mob Doctor). The Michael J. Fox Show isn’t a well-designed family sitcom that happens to star Michael J. Fox, it’s a bespoke vessel, expertly tailored around the wants, needs, and Q rating of its lead. It’s not a great series or even — yet — a good one. It’s a smart-on-paper idea that was handed a 22-episode order and forced to make do.

The strongest argument in favor of The Michael J. Fox Show is its cast. Fox himself remains a marvel, an utterly undiminished presence despite his affliction. As Annie Henry, Mike’s schoolteacher-and-karaoke-queen wife, Breaking Bad‘s Betsy Brandt is finally able to relax. Freed from the heavy rocks and minerals that weighed her down as Marie Schrader, she’s a warm, vivacious treat. Also strong is Juliette Goglia as the Henrys’ [sigh] precocious teen daughter, Eve. The plots given to the 18-year-old Goglia may as well have been heirlooms from her grandparents’ generation — a recent episode concerned Eve passing up a chance to see a concert (the New York City–based Vampire Weekend were, apparently, “in town”) because her innate goodness wouldn’t allow her to abandon an uncared-for puppy — but she’s a lively enough performer to make them feel fresh-ish. And I wish nothing but the fattest of paychecks for the massively gifted Wendell Pierce, forever known as Bunk on The Wire. Pierce’s part — Mike’s hound-dog producer/pal Harris — is the sort of barely sketched-out nothing often handed to minority performers on supposedly “broad” sitcoms, but Pierce makes it work thanks to his limitless charm and irrepressible wit. After years of low-paying, little-seen gigs, he deserves a wider audience and extra zeros in his bank account. It’s just too bad he has to dress up like Kenny Rogers to get them.

It’s a pleasant enough crew, and with some savvy on-location Manhattan shooting (as well as a truly throwback expansive Manhattan apartment — replete with a kitchen filled with shelves of apparently unused vases), The Michael J. Fox Show often looks like the very model of a classic urban sitcom. But, as of yet, there’s no there there. Though recent episodes have wisely dialed down the on-the-nose Parkinson’s humor (one of the pilot’s better gags was the sight of Fox rolling helplessly in an office chair), the series remains relentlessly sunny in a way that doesn’t reflect good cheer as much as it does a profound fear of clouds. With little in the way of antagonism to drive story — despite the show’s tepid efforts, a sad-sack middle-aged intern is neither funny nor compelling — Fox is forced to turn repeatedly to Katie Finneran, who plays Leigh, Mike’s sister, as a rampaging egoist on loan from a lesser Bravo reality show. Whether writing a children’s sex book about a man who turns into a horse or installing a stripper pole in the Henry apartment, Finneran gives the part her all, but that proves to be way too much for a sitcom clearly more comfortable splashing around in the kiddie pool.

It’s natural in the early going of a comedy to see characters still being sorted out, but Fox’s feels particularly unformed as family members’ personalities vacillate wildly from episode to episode. Some weeks eldest son Ian (Conor Romero) is deluded and cocky, others he’s simply an idiot. The writers seem unable to commit to whether youngest child Graham (Jack Gore) is wiser than his years or, essentially, a baby. This wobbliness carries into the scripts, which lurch from attempted farce (Leigh has bedbugs!) to cloying sentiment (family matters most!). These aren’t necessarily reasons to stop watching The Michael J. Fox Show, but I’ve yet to see a compelling reason to start. Successful family sitcoms are rarely advertisements for the niceness of a particular family, they’re pliable canvases for the comedic points of view of their creators and stars. (Modern Family, clearly a model, has a distinct tempo, clearly defined relationships, and built-in conflict. But you know what else it has? Jokes.) Showrunner Sam Laybourne has a remarkable opportunity here; no one gets a guaranteed 22 episodes to find his rhythm. Too bad he doesn’t appear to have much to say.

After seeing him flash an unexpected and self-aware edge on both Curb Your Enthusiasm and The Good Wife, Michael J. Fox’s soggy choice for a comeback vehicle is particularly disappointing. Building a sitcom, even a family sitcom, around that sort of tarnished character rather than an aspirational saint would have been a far braver, and likely more rewarding, decision. But the fact that both he and Robin Williams chose instead to return to TV in familiar guises — cuddly and unhinged, respectively — is coldly logical, if uninspiring.

Not all television needs to be challenging. Networks and audiences alike are always in desperate need for comfort food. The problem with The Crazy Ones and The Michael J. Fox Show is that their particular style of meat loaf is both old and and barely reheated. In their marketing, both CBS and NBC crowed loudly about welcoming Robin Williams and Michael J. Fox home — both in a corporate sense but also in that we, the audience, would be welcoming them back into our living rooms on a weekly basis. That sort of thinking may have flown in the past, but it seems particularly myopic now: Thanks to Netflix and Hulu, the beloved past TV incarnations of Williams and Fox are always available at the touch of a button: warm, wrinkle-free, and vibrantly funny. Going forward, getting our attention will require a lot more from stars than just showing up. Mainly because, these days, they’ve never really left.