口是心非

I don't know why I do this. This, as in, say something when I'm thinking something else. Example, if I'm excited about something, I downplay my excitement to a level of indifference. Likewise, if I don't like doing something, I try my best to act somewhat excited and go along (although I have feeling I'm not very good at this). The reasons I've come up with to explain this behavior are quite irrational. I think I'm only alienating people, instead of having them think I'm easy to get along with.