Medical school dropout Wallace (Daniel Radcliffe, again proving he's more than Harry Potter) falls for quirky illustrator Chantry (Zoe Kazan) almost as soon as she comes up to him at a party.
But as in any good romcom, the odds are against them getting together. Wallace has a dead-end job, a grudge against his ex, and lives in his sister's attic. Chantry has a great job, a gorgeous flat - and a long-term boyfriend who is a lawyer for the UN.
She does, however, want to be friends; and so begins a bittersweet tale of unrequited love that Wallace can't own up to. He decides that having Chantry in his life at all is better than losing her. While you spend most of the film rooting for them to be together, you can't fully support the idea, as Chantry's boyfriend is pretty great. Bummer.
There are some howl-out-loud-with-laughter moments (the "window" scene will leave you reeling), and hilarious supporting characters. But the biggest appeal is What If's "realness": it's set in Toronto rather than the usual NYC, San Francisco or LA; the dinky Radcliffe and Kazan look like people, not airbrushed dolls; and an obsession with an unlikely sandwich, the sort of thing that cements the best friendships.
Contains strong language