Yes, you are correct about Vietnam. I blush to admit that I actually volunteered to go to Vietnam. I know it sounds crazy, but there was a reason. Lieutenants in my battalion at Ft. Bliss were getting surprise orders to be in country within 20 days. I decided I would rather know I was going, and when. So I volunteered. As a result I ended up attending a six-week refresher course at Ft. Sill, and had 30 days to arrive in country after that. Don't believe them when they say, "Never volunteer."
My five years in the military was both challenging and rewarding. I have no regrets for my service.