Hannah , Alex and jessica

It illustrates her insecurities, and probably she felt betrayed because they didn't tell her upfront. I've known girls like that, regardless of how hot they are, they get upset when guys ask about hooking them up with one of their friends- the one who gets all the attention.

I took it more as a way to tell the story of how everything came to the point to 'the worse day of her life' (her words).

Without her 'complaining' about the smaller things, we would have no backstories.
I think it was more about losing her friends, feeling alone. So we had to see the J&A hookup, list, revenge/misunderstanding.

And the whole point, I thought, was to show how selfcentered the most of us take any given situation in our lifes.
We only see our reality and this makes for many misunderstandings.

For example- traffic, someone cuts you off, you might curse, call the person an idiot... how often do we think "oh, maybe that persons parent died today and they got distracted, didn't see me and accidentally cut me off - poor person x". No, we just see it our way and how we feel. So they had to do the same with the Hannah character.

I think she was mostly upset that they kept the relationship secret and drifted apart instead just telling her what they were doing. She didn't care about their feelings for each other, but that they left her out once they started liking each other.

Also, everything about Alex was gay. It made no sense that he dated Jessica.

You missed the whole meaning of why she was upset. It was sorta screwed up that they ditched her that way.