At this stage in my life, about the only thing that keeps me up at night is too much caffeine at the wrong time of day.
Seriously, though, while I would not say life is great for me, it is pretty damn good. Our finances are in order. My wife and I are both employed full time in a crap economy. We have an exit plan that we are looking to put into place in a couple of years.
When I am not able to fall asleep right away, it's usually me feeling hard done by because my wife said no to some love making even though it's been a while. And if that's the worst that happens to keep me awake, then I'm in a pretty good place.