All too often, when I wander through a megaplex lobby, I'll glance up at a poster for some forthcoming romantic comedy, and the two stars beaming at each other will look as if they've been placed there by accident, a celebrity dating service -- by anything but the destiny of love. Ben Stiller and Jennifer Aniston? Why not Lisa Kudrow and John Cusack? Josh Hartnett and Maggie Gyllenhaal? Jessica Simpson and DMX? (I mean, really -- why not?) Putting these pairs together isn't about chemistry; it's about the physics of meshing demographics. These are romances shaped by agents and focus groups and by the directors who think like them. It's no wonder movies like Along Came Polly have all the spontaneity of corporate mergers.
Which is not to say that they're always unwatchable. I chuckled a few times at ''Along Came Polly,'' if only because Ben Stiller is willing to stoop as low as he can to turn himself into a clown prince of humiliation: the man who would be dork. As Reuben Feffer, a risk assessor at an insurance firm, Stiller is playing a domesticated masochist, a fellow so cautious and tame he won't dare to eat from a bowl of nuts at a bar for fear of consuming everyone else's bathroom germs. It's enough to make you wonder how he got to be buddies with Sandy (Philip Seymour Hoffman), a tortured vulgarian who tells you when his flatulence carries a little something...extra. (Hoffman might be playing the Method Jack Black.)
The setup for ''Along Came Polly'' is ''The Heartbreak Kid'' in reverse, with Reuben, on the first day of his St. Barts honeymoon, discovering that his wife (Debra Messing) has entwined her flippers with a French scuba hunk (Hank Azaria). Back in New York, he's despondent until he meets Polly (Aniston), a former junior high acquaintance who has grown up into a lovely, if flaky, underachiever. The two appear to like each other, so the only real obstacle to their affair is Reuben's mania for cautious self-control.
Having giggled at ''Meet the Parents'' and, even more so, at the underrated ''Zoolander,'' I have stumbled, I think, onto the golden principle of Ben Stiller comedy: When he acts like an obvious, uptight moron, as in the bit where Reuben tries to plunge out Polly's stuffed-up toilet with her $200 loofah or dances at an underground salsa club as if he had five tangled limbs, he's no funnier than Adam Sandler on a lukewarm day. But when Stiller acts like an obvious, uptight moron who has decided he's cool, he's extremely funny. Witness his return trip to that salsa floor, where he does a disco tango routine swishy enough to make Ricky Ricardo retch.
It doesn't say a lot for one's leading-man prospects when you're at your funniest looking bad while trying to look good. Playing men named Feffer and Focker, Stiller, with his choppy haircut and simian stoop and gritted-teeth grin, has become the Last Jewish Loser in a world of streamlined Hollywood WASPs. ''Along Came Polly'' is nothing if not a chick flick for guys. The fantasy of Stiller rescued by Jennifer Aniston as a taut-bellied, genially undemanding princess whose greatest flaw is that her apartment is a bit messy could easily prove more pleasing to men than to the women who may wonder if she's settling. I'm enough of a fan of Aniston's ordinary-girl sparkle to feel that she generates a facsimile of chemistry just by gazing at Stiller with equal parts disparagement and warmth. But ''Along Came Polly'' leaves you wondering what these two will look like when the honeymoon is over.