Exactly! I too expect a certain level of "behaviour" in the people I choose to have a round me. But the difference between now and previously is that now I know that if people act differently than my expectation, then I can enforce a boundary. For example, I am still in business with my ex. Some days he tries to take out his frustrations on me. I expect that people in my life don't do that, but I can't get him to change his behaviour. However, I can choose not to speak with him and in the long run can make a decision about whther or not I want to be in business with him. In the past I would have done everything to get him to stop and driven myself into a frenzy when he wouldn't.
Another thought - I have found that sometimes people will live up to the expectations of others. e.g. very often the "black sheep" of the family will continue to play that role well into adulthood. The expectations become labels.
People are full of surprises - it would be a boring world if we weren't.