Happiness, we say, is a choice. Happy people understand this, while unhappy people struggle with judging themselves for not being able to easily shift to a happy state of mind.
The first step towards moving into a happy state is to understand that happiness is something we need to learn and, for some reason (that we will not discuss here), school teaches everything else but happiness. Use the "school of life" to practice happiness and remember that your "choice muscle" needs to be active all the time. Always notice you have options in everything you do, think or feel, and that you choose the things that are best for you.