The romantic-comedy formula depends on our wish to see two tentative soul mates finally get with each other. But this backfires badly in What If, an unctuous rom-com that runs its characters through every plastic cliché of a pre-Oscar McConaughey vehicle, ultimately causing us to root against the vacuous couple and their predetermined happy ending. Daniel Radcliffe plays Wallace, a sour singleton in Toronto who goes to a party and meets Chantry (Zoe Kazan). She has a boyfriend (Rafe Spall), swiftly jettisoned from the plot via a business trip, leaving her plenty of time to kill with Wallace. Among their wacky adventures: a dress-shopping excursion during which Chantry's garment gets stuck over her head and Wallace crawls into the fitting room to free her.
That's about as fresh as the story gets. What If features best friends offering advice, sexual tension while skinny-dipping, and awkward wedding toasts. Wallace flies across the Atlantic to see Chantry; her boyfriend punches him in the face. Director Michael Dowse (Take Me Home Tonight) sets the tone on high quirk, and Radcliffe races through lines like ''The-whole-premise-of-deep-frying-is-that-it-makes-everything-taste-better,'' as if not taking a breath somehow makes the material more original. The script has an odd fixation on the scatological, with references to impacted colons and diarrhea, and Wallace's vulgar, horny buddy (Girls actor Adam Driver, really stretching) speaks about eating one's waste. People, he claims, can recycle their own by-products only a certain number of times before they become toxic. In that, indeed, the film has the beginning of a point. D+