Whatever we focus on is bound to expand [1]
I have learned from experience that happiness is an acquired skill. There is always something to complain about, even in the best of times. Happiness is not an objective reality so much as a subjective decision. Chronic complainers miss the boat.
Many people are addicted to suffering and have a mental habit of pointing out the worst in people or situations. Not only are they robbing themselves of joy, but their failure to appreciate all the goodness that life has to offer actually diminishes all that good. Both our blessing and our condemnation have power. Thinking that something is bad has the power to make it so in our experience.
Children are one of the greatest lessons in happiness, constantly challenging us to enjoy the moment, as the next one will not be the same.