I got shot at (a lot) and blown up in Afghanistan when I was Army Infantry, but I didn't really develop PTSD (according to the psychiatrists). Maybe because I knew what I was getting into and what to expect.
Recently, though, I was in a major automobile accident with my family, and I damn sure have PTSD coming out of that. Americans DRIVE LIKE ASSHOLES without respect for other drivers. I have a heart attack every time a car aggressively pulls up to a stop sign and stops well past the stop line