Most of the time, when I am happy, I find myself wondering whether I deserve to be so happy. Then I start finding reasons to not be happy and pretty soon I am unhappy. Strange how that works.
Happiness just does not last as long as we would like because of the cascade of thoughts that follow the feeling of happiness. Feeling looks to thought for validation and this is a set up for failure. Thought does not know how to validate feeling. Thought does not understand feeling!