"Nobody rises to low expectations."
- Calvin Lloyd
I find that I treat this issue very differently in my professional versus my personal life.
At work, we set high expectations, because if you strive for mediocrity, that is exactly what you will get.
In my personal relationships, excluding my wife and her immediate family, I have learned not have any expectations, that way, it is hard to be disappointed or hurt. It has served my well over many years, and I do not see it changing anytime soon.