'What If' an iffy romantic comedy

"WHAT IF" is "When Harry Met Sally And Dithered."

Daniel Radcliffe is lovelorn single guy Wallace, who meets his soulmate, Chantry (Zoe Kazan) at a party, though she's already deeply attached (to Rafe Spall).

They agree to be friends, and we again examine the question of whether a man and a woman can ignore the sparks flying between them and exist as platonic creatures. The answer in "What If" is obviously "no" - every Wallace/Chantry encounter deepens their intimacy and attraction.

The process in "What If" is protracted beyond belief or endurance. While Wallace rolls through life as a third wheel, even his inveterate lady-killing bachelor pal (Adam Driver) finds true love (with Mackenzie Davis).

As Wallace equivocates, his behavior starts to look less like chivalrous respect for the feelings of his spoken-for gal pal and more like emasculation. They skinny-dip, she invites him to look at her body, they cuddle.

And Radcliffe, of all people, should know what happens when you dither. Hermione ends up with Ron Weasley. J.K. Rowling, years later, ends up admitting the whole thing was a grave mistake, that she got the romantic wiring all wrong. Which is probably a sales pitch for her planned sequels, which find the principles in middle age. Hermione drinking and lonely, Ron spending more and more time at Ladbrokes betting on the quidditch, Harry recently widowed . . .

Wait, where was I?

Right. "What If."

The narrative lines of this comedy are readily detected. It remains for the cast to give them some detail and freshness. Kazan is an appealing performer, has decent chemistry with Radliffe and some of the writing is clever.

The movie though, stops playing in your head the moments the credits finish rolling.