The best dating advice I ever heard a pseudo-professional give was that sometimes, the answer is just no.
"(500) Days of Summer" was better than I feared it might be - not amazing, but pretty good. Summer was less of a stereotypical manic pixie dream girl then I thought she would be, although she does have a lot of those characteristics. And I appreciated that, throughout the movie, we did get repeated reminders that maybe, just maybe, Tom was idealizing Summer and their relationship.
Summer is not a particularly fleshed out character, but since the movie is basically entirely from Tom's point of view, I can pretend that that's because Tom never really saw the actual human being that she was and only saw the pieces of "dream girl" that he wanted. I was irritated that Summer talks about how they've been fighting a lot but ... we never really see that. There's only one scene in which they really fight, and Summer's description makes it sound like much more. Again, maybe Tom just doesn't want to see/remember that part of the relationship, but that just makes him seem that much more out of touch with reality.
I did think that Joseph Gordon-Levitt was very good in the role. Tom, as a character, though, was really kinda annoying. People who are all talk and little action make me tired. It takes him way too damn long to even try to get to know her, and that action is mostly taken out of his hands anyway. He takes no action in his life until he's so far down that there's pretty much nowhere else he can go.
I had far more sympathy for Summer, who - manufactured quirks aside - seemed to know who she was and mostly what she wanted. She isn't afraid to take action. Her behavior toward Tom, especially at the end, might seem cold, but I saw it more that, for them as a couple, her answer was just "no." She likes him, he's interesting, but ultimately she does not love him, and staying with him just because he's nice isn't a good enough reason.
Other good things to read about this movie:
and from Jezebel