Practically everything about What If is irritating — starting with its meaningless, question mark-less, title down to the way its relentless romcom cliches prove annoyingly engaging.

Director Michael Dowse adheres to the format established by the likes of Jennifer Aniston and Cameron Diaz so staunchly that a better (more accurate) title would have been Friends Without Benefits or Strings Attached.

Daniel Radcliffe and Zoe Kazan star as Wallace and Chantry, two quirky, nerdy Toronto misfits/soul-mates whose affection seems destined to remain platonic. This is principally because Wallace’s awkward Englishness and parents’ infidelity mean he refuses to try breaking up Chantry’s five-year relationship with her alpha male boyfriend Ben (Rafe Spall).

The plot is perfectly predictable but Elan Mastai’s script is just sharp and rude enough to help What If resemble an extended episode of the US series Girls, not least because the reliably lively Adam Driver replicates his role as Adam in Lena Dunham’s TV show to play Wallace’s best friend Allan. Can’t he play someone whose name begins with B?

But while Driver’s unorthodox energy and Kazan’s charm shine out of the screen, Radcliffe’s pedestrian performance means Wallace is not the amusing oddball we’re supposed to see but just a scruffy dullard.

And Radcliffe’s seemingly obligatory nude scene is almost as off-putting as his exuberant dancing when Wallace and Chantry go clubbing. But as a sweet scene where Chantry becomes stuck in a dress confirms, the element that rescues What If is, crucially, the fact that they have real chemistry.