Happiness is to love and to be loved.
But a happy moment it could be a dinner with friends, to read an interesting book, to watch a romantic film, to go for a walk through a beautiful landscape or to eat a chocolate icecream.
I only remember one song about happiness and the title I think is Happy day. But there is a song of Coldplay called Viva la Vida that I really believe speaks about ¿happy old times?.