Positive people are happy people. Happy people are pleasant to be around. Being around people you enjoy improves your own disposition and desire to put forth effort.
Being positive should not be confused with satisfaction. Telling someone to be satisfied makes little sense to me. For example, after a presentation I ask myself, “What did I do that was good?” and “What can I improve?”
We always have the opportunity to learn and grow. If we were satisfied, we would never grow. It is the feelings that emanate from growth that bring satisfaction, joy, and happiness.
If you wish to become more effective, unload the burden of thinking that you need to be satisfied in order to be positive or happy.