Having or spending money doesn't guarantee happiness and not having/spending lots doesn't make you miserable. The extreme frugal people I know get pleasure from saving money. I don't know what the ultimate goal might be but I've noticed they tend to gamify the process of saving money by buying stuff on coupons, discounts, bulk, etc. and they seem to get a rush out of it (a lot of times its buying useless stuff in excess just because it was cheap or on sale). To me it doesn't make any sense to save money just for the sake of saving money and I'm on the frugal end of the spectrum but who am I to judge what makes someone happy.
The retirement spending rates noted in this thread are pretty eye popping but I'm glad there's people out there spending that kinda dough - great for the economy and its what helps incomes rise since the high spenders amongst us will demand pay increases to keep up with their lifestyle and everyone benefits.