The following quote is taken from Bertrand Russell’s book The Conquest of Happiness (1930), a fabulous work in which Russell mixes philosophical analysis and practical thinking in order to help people cure unhappiness and find happiness. 

“The secret to happiness is this: let your interests be as wide as possible, and let your reactions to the things and persons that interest you be as far as possible friendly rather than hostile.”

I know many people will reply, “easier said than done.” However, I would urge you to at least try keeping this thought in your mind as you go forth each day into the world, and see if it at all changes your behavior. You might be surprised by your findings.