I've always laughed at the trope of an infantry soldier who turns out to be a badass. I've met a LOT of infantry soldiers. Snipers however, are actually trained and go on exercises where they stalk and outmaneuver the enemy.

The snipers I've met (I am no sniper), were second enlistment guys with combat experience. They were mature and calm. They were wicked smaht. A good sniper is playing a chess game with the enemy. There are times when the task calls for a muscle-head, but not sniping.