How difficult do you find always being the bigger person?

If you have to deal with someone on a regular basis who has crappy communication skills, is extremely sensitive, and always turns their behavior around on you…

How hard is it for you to be the adult every time? Some people find it difficult, and other people find it easy. What makes it so easy/hard for you? Does your patience level depend on how close with the person you are?

Inspired by this question.