It's a movie you can pass off as a silly fantasy where a hot girl like Alice Eve would never fall for a guy like Jay Baruchel's character, but the script does a really good job showcasing why she'd want to stop dating the same guys who break her heart and why someone like Kirk is who she should be with. And I feel the insecurities and the apprehensiveness they give to the Kirk character is something ever guy can relate to who has had insecurity issues and they're dating a really pretty girl.
The third act scene where they're about to have sex for the first time encapsulates the entire crux of the movie. Kirk looks at himself as boring, unattractive, and not worthy of being loved because he's been bullied and broken down to that point. He doesn't realize that Molly knows he has faults but she wants him anyway.
This movie and movies released around this time like Celeste and Jesse Forever are the comedies I really wish were still being made today. Just sweet laugh out loud movies you can watch over and over again.