The more I grow, the more I realize that happiness is a choice. While there may be many reasons to be sad and depressed, there are also many reasons to be happy. We as human being have the power to choose happiness.

What differentiate us from animals is our ability to think about our thoughts. We do not necessary control the thoughts that come to our minds but we control what we can do about the thoughts. For example, a thought might come to your mind to overindulge in alcohol because at that moment you might be in the "mood". - at the same time you can think about that thought and realize that the next day you have to work, and therefore you decide against over doing it.

The key is to always or at least try to always think about our thoughts. Just like a PID Controller. - constantly comparing our thoughts to our chosen values. When the thoughts move away from our set-point (values), we correct our thoughts (MV change) to align to our set-point.