Iím a 12-years old kid.I donít want to life an unhappy life

Many young people in the city that I live in live an unhappy office life and got a very little personal free times.Their working hours is long and theyíre angry with their boss,their costumers and their workmate every day.But they need to countinue for their salary.

I donít want to be unhappy like them when I grow up,what should I do?