My expectations were reduced to zero when I was 21. Everything since then has been a bonus. - Stephen Hawking
Expectations are a funny thing. Sometimes they’re based on reality at least to some degree. Other times expectations are not much more than wishful thinking.
When you expect a situation to be different even though the same thing keeps happening then you’re not using your thought process wisely. For example, lots of us have a relative that we visit once or twice a year. Not really happy about going there because this person is pretty negative. Even so, you think to yourself this year it’s all going to be fine.
You may have just set yourself up for a great disappointment. If you’ve known this person your whole life and they’ve always been negative, what craziness would make you think that this time will be different? This is a situation where having a positive, maybe even miraculous expectation, will do you no good. A reality check at this point might be more helpful. It’s better to recognize difficult relatives for who they are, do your best to accept the situation as it is and likely will be, and probably limit the visit for your own sanity.
On the other hand, if you have an expectation that you will do well at some task, this may be an advantage. Sometimes having high expectations of yourself or of someone else can motivate you or them to try harder, to practice more, and to put in more effort to meet those expectations. The difficulty becomes when the expectations are too high, and so impossible to meet. Expectations need to be outside your zone of comfort just enough to require you to grow from the experience and not so much that they are impossible to reach. Being conscious of your own expectations of yourself will help you use them effectively.