There is a Chinese saying that goes: “If you want happiness for an hour, take a nap. If you want happiness for a day, go fishing. If you want happiness for a year, inherit a fortune. If you want happiness for a lifetime, help somebody.”
It can be elaborated more with a short story
A professor gave a balloon to every student & asked them to inflate it, write their name on it and then throw it in the hallway.
The professor then mixed up all the balloons.
Next he asked the students to find their balloons in 5 minutes.
Despite a hectic search, no one could.
At that point, the professor told them to take the first balloon that they found and hand it over to the person whose name was written on it. Within 5 minutes, everyone had their own balloon.
The professor then said to the students -
“These balloons are like happiness. We will never find it if everyone is looking for their own. But if we care about other people's happiness, we'll find ours too !”
"If you always seek for your won happiness, you will never be satisfied. If your happiness depends on money, you will never be happy with yourself. Be content with what you have, share it with other people; rejoice in the way things are. When you realize there is nothing lacking, the world belongs to you."