just like the blind can't lead the blind, an unhappy person can't make someone else happy. you make people happy not by doing things, but by first being happy, and then teaching them your secret, either by example or by word.
hence, focus on your own happiness. be selfish about your happiness. because the responsiibility for your happiness lies on you and you alone.
conversely, doing something just because it will make someone else happy, will make you unhappy. and the other person may learn to rely on you or other people for their happiness. and this situation makes nobody happy.
so pursue your own happiness relentlessly. nobody will even realize you're being selfish about it, unless you tell them. and when you find your happiness, you'll find your work is pretty much done.