God where do I start. I'm a couple beers in so consider that when you read.
I came back from a deployment in southern Afghanistan in 2012. I was an EOD officer, am out now, and had seen a significant number of servicemen get fucked up by pressure plates. Not on the FOB seeing them arrive to roll 3, not in story boards, but on patrol, embedded with infantry, with my teams, actually not at a desk. Never felt bad about anytime I fired my rifle, always those images of guys who just had a bad fucking day haunted me. All of my team leaders received purple hearts. I saw a guy literally get his nutsack blown off along with his legs. I applied a tourniquet and an israeli bandage to a couple people. Nothing ever happened to me, never got hurt, always managed to step over the 'lucky' spot, the bzzzzzzzewwww of AK fire never hit their mark with me, etc.
Within a couple months the BDE I was supporting was replaced by a BN and all of that land that we made 'progress' on was quickly returned to the shit heads that put all the bombs in the ground. Within less than a year I saw a shit ton of guys who I thought were better than me give up their legs/arms/lives for what I thought was a good cause. The gore never bothered me either. But seeing a west point LT soccer star lose his leg, or a junior enlisted kid take a glass mason jar IED to the face, or a senior medic lose his balls, or the morale collapse in a company after their First Sergeant got KTFO by an IED blast and lay motionless on the ground during a 3 day turned to 8 day dismount killed me.
Fast forward to a couple months after returning and I'm doing all the things they tell you your Soldiers are gonna do. Have a couple shots and ride my motorcycle really fast, sleeping with everyone within a 40 mile radius without protection, mixing tannerite (making my own lol) and shooting it way too close in the boonies, drinking a 6 pack a night. I'm making terrible life decisions, I have a girl I went to college with move in while she's running away from her shitty family, we live together, I think I love her, it quickly turns toxic, and next thing I know I have a gun in my mouth while I'm doing my laundry in my house wondering what it would be like if I just did it.
My dog comes over to the laundry room, ears back with the 'puppy eyes' on and for whatever reason I just put the gun back in the drawer and go about my day. Eventually I make my way to behavioral health, never ever mention the gun in the mouth episode, lie about my deployment experiences, and want to focus only on my (3rd) failing relationship. Fast forward a couple years later I finally tell my shrink the truth, he's like "holy fuck" and now I'm getting meds and help and have a great job and life is good. That's my personal experience in a nut shell. Not 100% sure it was all the deployment stuff, probably had a lot to do with interpersonal relationships and work relationships. Plus a few decisions I made when choosing teams for certain missions that lead to people dying/getting hurt etc. When I think about my grandfather being a POW in Germany for 18 months I feel like a giant pussy too so that never helped lol.