3) trying to be friend
(3) never lasts. It always turns into (1) dating, (2), fighting, or (3) avoiding each other.
They don't just reuse plots. They also reuse characters. In other words, the people doing the fighting, and the people doing the dating, are the same small group.
When they branch out it usually has to do with either an affair, hurting someone, or more often both.
It'd be nice if it was just a fantasy, but The Hills is rather similar, except without any script.