There may be times when you wish people would act differently. For example, let's say you want someone to invite you to a gathering or some kind of social event. If they don't, you feel bad.
In that case, you can ask them to do so next time. Then they will act the way you want them to, and everything will be fine, right? Wrong. You still feel bad. Why? Because they should have acted that way regardless of your request. That's unreasonable.
It's wrong, and it's not really what you wanted. You don't want their behavior to change. Behavior is just an expression of some kind of feeling, like "they like me." That's what you want to change. If they didn't invite you, it's an expression of an underlying feeling. You feel that's the real problem.
It may sound obvious, but pay close attention. It can happen anywhere. You have to pay attention to what you are trying to adjust. What do you really want to change? Behavior or underlying sentiment? Sometimes it's not easy to see.