This is normally an Averted trope. While the general population tends to think that most people can go through war and come out just fine unless they're 'wimps,' War Is Hell. Most war-based videogame and movie characters are shown to go through things that in real life would leave them completely unable to function, let alone live a normal life. Of course, this is one of those Acceptable Breaks from Reality, since the Main Character ending up a gibbering wreck or street person after taking so many hits to their Sanity Meter isn't a very happy ending. Almost any character who doesn't end up at least somewhat traumatized after war or other brutal events counts as an aversion, unless they're a psychopath (or in the lucky minority). See the Real Life section.
Analysis / Shell-Shocked Veteran