How to make people happy?

  How to make a person which in a bad mood situation become happy? It is too hard for me... If kids, that was very easy, I very well in make a kid happy back when the kid was sad.. But other than kids, I unable to make them be happy back when they were sad.... I'm wondering, what can I do to make people happy back? Anyone can give me advises? I want to learn the way to make people happy back because I don't want look my friends or people I know in sad condition.... Sometimes, I feel myself so kepo... People' things are people' things, why I so busy body, care this care that, kepo this kepo that, till the end, I only get bad rejected and hate by people.... Why I so stupid? Why I always doing somethings that I no need go do? I too easy care people' things... I am that kind of people which kepo people' things kepo till forget my own things.... Is it a good habits? Or that is bad habits? I want to change this habits, I don't want care too much, but the answer is I unable to change this habits... It is already become my lifestyle mode.... My friend told me she wanna suicide, wanna leave this world... At that moment, my mind was thinking why don't I suicide with her but till the end I encourage her not to suicide because it is not worth at all... If I wan suicide, I will do it myself but I won't call people accompany me suicide because I know this action is too awful stupid, only myself can do this stupid stuff... >.<