[W]hen you decide to define yourself as being in opposition to someone else, then you give that person immense power over you. That person doesn’t have to have anything to do with you, and often won’t; you’re the one who has to do all the work, tracking their positions and attitudes and setting your own life in opposition. In effect, you’re letting them live in your brain, all the time, without cost. Whereas they will think of you only when they have no other choice.
–John Scalzi on identity.
This is something, I’m ashamed to say, it took me a really long time to learn.