One person I friended on LJ due to similar fandoms ended up being one of the angriest, most bitter people in the world, and their posts were all about all the things and people they hated in their real life. I get venting, but I couldn't live with that level of negativity.

They also wrote a long fic that I liked a lot, stopped for a long time partway through, then finally finished it years later - with an ending that I hate, which confused and blindsided me for coming out of nowhere.

Ugh.