Sparks fly between Wallace (Daniel Radcliffe) and Chantry (Zoe Kazan). (F Word Productions)

The phrase “just friends” is near the top on the list of Things I Hate, right after tailgaters and cooked green peppers. “Friend zone” is also up there, nestled between people who text without turning that clicking noise off and turtlenecks. I don’t like anything that cheapens friendship and I particularly don’t like anything that insinuates that friendship is defined by its relationship to romance.

That’s part of the reason I liked “What If” so much. In the film, out Friday, the friendship between Wallace (Daniel Radcliffe) and Chantry (Zoe Kazan) is something worth having and worth protecting.

“What If” isn’t so much a consideration of the question of “can a man and a woman be friends?” (The answer is yes. Stop asking.) It’s more of a look at “HOW can a man and a woman be friends?” Wallace wants to get romantic with Chantry; that can’t happen, but he likes her enough to work at maintaining their friendship.

You don’t need romantic feelings to complicate a friendship. Having a nonsexual relationship with anyone you might conceivably sleep with is to live in a hypothetical situation. Something might happen, and “What If” convincingly shows a relationship that both people value enough to live in that space between “might kiss” and “have kissed.” Admitting that something might happen and choosing to be friends anyway doesn’t make the relationship some weak version of dating, but a strong version of one of the best relationships life has to offer.

In most rom-coms, friendship is only important if it leads to something “more.” Exceptions arise when puberty hasn’t hit yet, as in “My Girl,” or when the relationship isn’t central to the story, like with Lloyd Dobler and his two girl friends (not “girlfriends”) in “Say Anything.”

Romance is an easy subject for the movies because its stages, from first kiss to final fight (or wedding, depending on what film you’re watching), are nicely structured. But when does a friendship start — when you meet, or when you realize the other person can use a “Simpsons” quote in regular conversation? When does a friendship end? Most tend to do so quietly, with a slow dissolution due to distance or circumstance. A breakup tears the fabric of your heart, but the end of a friendship fades the entire cloth. A rip can be stitched up, but vibrancy lost is vibrancy gone.

Whether or not Wallace and Chantry end up together (and I’m not telling), what’s unique about their friendship is that they continually make tough decisions to preserve it — not because it’s a step toward or a substitute for romance, but because it, on its own, is important to them.

“What If” is a rare film that holds friendship not as a means to an end, but as its own reward.

Want more film?

‘Life Itself’ is the story of Roger Ebert & dad & me

Five documentaries you should see before you see “Korengal”

“The Railway Man” doesn’t quite get the gray areas of PTSD

“The Fault in Our Stars” shows the blunt force of cancer