Being around negative people is tiring, amirite?
I have a friend who is almost always in a negative/unhappy mood. She always seems to tease me, and while it is friendly, after a while it does hurt. Also, she doesn't like to admit she's wrong, or apologize (unless she's done something seriously wrong). It's tiring to be around her, but when she's in those rare good moods, I really enjoy being around her. It's quite unfortunate that she's this kind of a person.