What you and everyone else on this planet needs to understand is that mental health depends on the mind. There are piss poor and unlucky people who are manic, and really lucky people who are always miserable no matter what. It utimately comes down to brain chemistry. I can say that I have a pretty sweet life but I'm begging for it to end because my mind is so fucked up that I'm irritable at best. Most people are somewhere in the middle, where attitude and external circumstances can tip the scale one way or the other. But some people are simply always happy or unhappy no matter what.