What If

“What If” doesn’t exactly put a new spin on the tired romantic-comedy formula — and the meaningless, arbitrarily assigned title doesn’t help — but it does apply enough wit and relatable human behavior to the formula to make it recommendable, which is more than you can say for most rom-coms.

Directed by Michael Dowse (“Goon”), this saucy-mouthed film stars Daniel Radcliffe as Wallace, a sad sack med-school dropout whose heartbreaks have made him cynical. He befriends Chantry (Zoe Kazan), a doe-eyed animator who, alas, already has a long-term boyfriend (Rafe Spall), raising the eternal question: can Wallace and Chantry be “just friends”?

Elan Mastai’s screenplay (adapted from a play by T.J. Dawe and Michael Rinaldi) has everyone speaking with glib sarcasm and playfulness, a mostly successful attempt to mimic the attitudes of modern twentysomethings that only occasionally feels forced. The story is hurt by a few never-plausible tropes (skinny-dipping gone wrong; spur-of-the-moment overseas plane trips), but Radcliffe, Kazan, and castmates Adam Driver and Mackenzie Davis are breezily charming. A rom-com about people who aren’t idiots? What a concept!

B- (1 hr., 42 min.; PG-13, a lot of profanity and vulgarity including sexual references, partial nudity.)