Happiness is the natural state of things. It takes a lot of practise and energy to be miserable and I have no idea why some people prefer misery to happiness. It is no doubt one of the great mysteries of the universe. You might have noticed that life tends to naturally move towards happy outcomes. This is because at the root of what most people desire, whether that be a house, a fancy car, or an adventurous holiday, is happiness. People do not tend to desire things that make them unhappy (unless they are part of the band of people that practise daily misery).
Want a challenge? OK, today why not do something that makes you happy. It can be anything. If you succeed in this one small task then and only then can you do something to help another person feel happy.