I Don't Understand Why People Like This Movie

I don't know the source material, so maybe that has something to do with it, but I don't understand why this movie seems to have such strong support amongst those that have seen it (which wasn't many when it first came out).

What is the appeal? The main character is a complete jerk and through Michael Cera's performance evokes no sympathy or empathy from the audience. What are the redeeming qualities of Scott Pilgrim? All I saw was a pouty, whinny, "guy" who cheated on and lied to his younger girlfriend. Ramona Flowers was miserable and lifeless too, what was her appeal?

I wanted to like the movie, as it was made in and takes place in Toronto. Despite the fun familiarity with places like Lee's Palace (which was recreated in amazing detail inside a studio) I found myself not liking anyone who occupied the scenery.

Also, it's supposed to be a comedy. It isn't funny.

Maybe someone could explain the appeal.