Movies and TV make war look approachable and they never show how bad it really is. Even the horrific D-Day landing that opens Saving Private Ryan (as good as it is) doesn't conjure up the actual terror that exists when you are under fire and are scared that an unheard thing is going to slam into you and end, or alter your life. Add to that the carnage happening to your buddies around you and it is enough to make you want, no need, to forget the details. You can't keep the memories out of your dreams, but, while you are awake, you can do other things to pretend those experiences didn't happen, or at least suppress them. When an idle question rips away that shield of forgetfulness, it is very hard.