You are not responsible for anyone else behaviour. Do things because you want to never because you have to. Disappointment comes in when you swap the two.
There are nice and kind-hearted people out there, who will go out of their way to help, even strangers.
If you do something good for others, never expect something in return. Just do what is necessary and be thankful for all the blessings. ~ Leonora Digamon
You can be kind without expecting anything in return. Expectation is the root of all heart break.