...if you understand what it's telling you and act appropriately.
Let's take a simple model for this feeling good/bad situation: test score. If your score meets your expectation then you'll be feeling good and vice versa.
So does with your feeling about yourself. If you are feeling bad then there are certain standards which you do not meet. We unconsciously evaluate ourselves to our standard which results in either satisfaction or dissatisfaction about ourselves or our life.
