> Most of our negative emotions are a waste of time and energy.

In a different frame, most of our negative emotions are there to help us - by signifying that something is wrong. You could be thankful for having them so that you are prompted to investigate what's wrong. It's only when we forget that feelings are only a part of our experience and start to identify with feelings (positive and negative) that trouble arises.

I really mean that wallowing in our negative emotions is a waste of time and energy.