These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ass Pull: The Reveal that Hannah is Cal and Emily's daughter is this to quite a few people.
Designated Hero: Robbie is presented by the film as a plucky, charming kid who never gives up on his love of his babysitter, even when the odds are stacked against him. Unfortunately, his love quest involves constantly following the girl around badgering her to date him, staging elaborate displays of affection that make her a laughing stock, acting like she's cheating on him when he finds out she likes someone else, and even turning his valedictorian speech into a passive agressive rant about not believing in love anymore because a crush turned him down. Add in the fact that this comes to light because she caught him masterbating to her, which he has absolutely no embarrassment about, and how he truly seems to believe he's entitled to a relationship with her because he's "nice", and many people end up seeing him as a Creepy ChildStalker with a Crush. The fact that he never learns a lesson about respecting people's wishes and not making them feel uncomfortable, and instead gets rewarded for his behaviour with nude photographs of his crush makes it even harder to root for him.
In his defence though, he's only 13, hasn't got the experience needed to charm girls that Jacob has and had just witnessed his father's big romantic gesture explode in his face.
Fridge Logic: 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, do none of these women that Jacob sleeps with then never calls again ever return to the bar?
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.
A couple were actually blocking Cal clearly from Liz' view.
Harsher in Hindsight: 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...
Jacob wants to help Cal, because 'he reminds him of someone' which happens three nights after he met Hannah. Cal reminds him of Hannah because they're father and daughter. Noticeably, they also both initially refuse Jacob when he offers to buy them a drink.
Jerkass Woobie: All the characters have moments where you want to hug them vs. moments where you want to slap them:
Cal's trying to get over Emily. Jacob helps him get back in the game. When Cal finds out that Jacob's dating his daughter (as in, seeing her for more than one night) his true opinion of Jacob surfaces, which makes him look like a hypocrite since he had no problem using Jacob's advice to treat women the way he didn't want his daughter treated.
Jacob's a womaniser who believes that women need to be subdued. After spending some quality time with Hannah, he begins to warm up to the idea of having someone special in his life.
Emily cheated on Cal for no justifiable reason. Only after Cal leaves does she realise that his absence has left a hole in her life and she genuinely seems to want to make things right.
Hannah got drunk and rebounded with Jacob because of an unrequited crush.
Jessica told Robbie that he was too young for her (4 years difference), then tried to seduce his father (27 years difference). Her plan to take nude pictures of herself and send them to Cal makes her look just as bad as Robbie to some.
David slept with a married woman and basically tried to hijack Cal's entire life. Despite this, He does seem determined to do right by Emily's kids, though.
Unfortunate Implications: Multiplecritics have called out the film for portraying a teenage girl attempting to supply an adult with nude photos of herself (ie, child pornography) before passing said photos on to a thirteen-year-old as an act of compassionate generosity.