* FridgeLogic: [[spoiler: Liz is presumably a very close friend of Hannah's. Has she never met Cal or seen pictures of him, enough to recognize that he's the guy Jacob is with at the bar? Not only that, but it appears that Hannah goes to the bar fairly often, yet never once ran into her father there.]]
** Also, [[spoiler: do none of these women that Jacob sleeps with then never calls again ever return to the bar?]]
*** [[spoiler: Hannah pretty much puts her social life on hold in order to study for the bar exam. She stops going out the same time Cal starts frequenting the bar. And Liz might only go to that bar with Hannah, rather than by herself.]]
* HarsherInHindsight: Robbie cites Ashton Kutcher and Demi Moore as an example of a younger man/older woman relationship that's gone strong. Cut to a year after the film's release...
* HateDumb: In-universe. Hannah's friend's reason for disliking her fiance is solely that he's nerdy and boring. Jacob is hot and fashionable so the fact that he's a womanizer is a non-issue with her.
* HilariousInHindsight: Hannah insists that her love life is not PG-13. Guess what the movie's rating is?
** Jacob wants to help Cal, because 'he seems kinda familiar'[[spoiler: which happens right after he met Hannah. Cal reminds him of Hannah because they're father and daughter.]]
* MemeticMutation: Robbie's ''Scarlet Letter'' "A is for asshole" speech in class.