Mental pain... Geez, what a curse. Physical pain, no matter how horrible, is basically a good thing. It proves you're alive, and "while there's life, there's hope". The problem with mental pain is that it REMINDS you you're still alive, day after day, year after year, if you let it.
Thank the Dark Gods for booze and shrinks
The cumulative effects of even a minor but lingering mentally painful thing can be far worse than any physical trauma. I mean, if you're all busted up, you're not much of a threat to anybody. OTOH, if you've got some inner demons riding you, you can hurt others and yourself, even if the worst physical trauma you've had is stubbing your toe.
I don't want to get into specifics of my own demons, because this ain't a therapy session. Suffice to say that I've been through a war and was a fireman for many years, so I've got more than the usual load of things I'd like to forget.
By way of example, though, consider this. As a fireman, when I'd pull up on an accident I knew was bad from seeing the state of the wreckage, I eventually got to the point where I'd actually HOPE to find victims screaming and writhing in agony. Especially if I recognized the vehicles as belonging to people I knew, which was about 1/2 the time.
It wasn't because I enjoyed seeing people suffer, but because suffering was really the most positive outcome. It was obvious that anybody involved was going to be hurt bad, but if they could scream and writhe, it proved several important things. 1, they had a heartbeat. 2, they had an airway. 3, they had a functional spinal cord. If you had those 3 things, I could work with you and do you some good. If you were missing 1 or all of those things, you weren't likely to make it, or wouldn't much appreciate it if you did.
Needless to say, when I caught myself thinking this way, that was yet another reason to drink.
Cheers
