I am ambivalent about the pursuit of happiness. It is surely a fugitive emotion that catches you unaware, rather than something you can chase and capture, or consciously create.
The continuing emotion that can sustain and keep one, is contentment. It is, I suppose what Farzanah describes in her post comes closest to it. You cannot be content if short of food, or heat, or a roof over your head, or facing serious problems, but to be content with how you are is far more longlasting than the essentially ephemeral feeling that is happiness (and all the more enjoyable because it is ephemeral).