To date, my time in the Air Force is still the largest fraction of my adult life. I joined at 19 and only got out in 2007 because I didn't want that life any more. There's more to say on that, but it will have to wait until later. I do still monitor the Air Force and have keep in touch with several folks on Facebook with whom I served in one capacity or another.
A former LtCol has written a pretty insightful piece on why he also got out. Please read not only the original post, but a post critical of him, as well as his rebuttal to it. It expresses thoughts similar to mine in why I separated from the service.