That's how simple the rules are. Another thing, to live a happy life is to make others happy also.
A happy community and environment makes all those people within it happy.
Do things you want,as long as you don't violate any other rule (especially the fourth one, okay?).
Live life with a +dream.
Live life with a +purpose.
Live life to the +fullest.
That is a +choice. +Happiness is still a choice, yours and yours alone. Then amazing life you'll be living.