Almost went in the Army. Went to MEPS, passed physical and they wanted me to be an MP. My Dad talked me out of it; said the day to day garbage of society would get to me mentally.
Can't say it has worked out too badly but it sure would have been nice to retire last year.
My brother has been in the Marines for around 17 years now, just made MSgt. and bought his third house. He's pretty squared away.