Writing needs to be rooted in reality. If it isn't real we can't project ourselves into the situation and it becomes distanced, rather like watching a television through a window. If the situation is real, however, we can put ourselves there. Then we can find it funny, or scary, or romantic.
So, if you take the characters on Friends, Monica is a control freak. She's more of a control freak than anyone I've ever come across, but it's an exaggeration of a tendency I see in others (not me, of course). I'm a fan of programmes like Time Team, and give me something about Ancient Rome and I'm there, but I can see that Ross takes his dinosaur enthusiasm too far, or rather, into the realms of comedy. Joey is dim, Rachel is vain, Chandler is Mr Beige, Phoebe is irritating - I mean fey. It's all normal human behaviour, but exaggerated.
Conversely, I didn't find Black Swan that scary - and I'm so easily frightened, I thought I was going to have a heart attack during Misery and had to leave the cinema. But it was about a world I knew little of, and the characters didn't seem grounded in any normality I recognised so it was harder for me to care about them.
John Irving said in an interview once that he writes the first draft full of normal people, then in the second draft he exaggerates them to make them funny. It's normality on superdrive. But it needs that kernel of truthfulness to work. Perhaps that's why I don't 'get' Phoebe - her character is the furthest away from my reality, and therefore she seems contrived rather than real.