One of the things psychologists used to say was that if you are depressed, anxious or angry, you couldn't be happy. Those were at opposite ends of a continuum. I believe that you can be suffering or have a mental illness and be happy - just not in the same moment that you're sad.

On the relationship side, if you teach people to respond actively and constructively when someone they care about has a victory, it increases love and friendship and decreases the probability of depression.

You can have meaning, accomplishment, engagement and good relationships, even if you are dull on the positive affect side.

Martin Seligman Quotes