I don't get it

How in the world is it possible for people to hate someone so much that they all get together in a little click and talk horribly about this person, and then all of a sudden they're nice to her face again and offering her support and embracing her again?

I hate clicks. I hate backstabbing and I hate DRAMA..... even online drama. And this is why I have stayed to myself and focused on myself and my family and ESPECIALLY why I have stayed away from most forums (not including the heart & photography forums).