Just recently a friend of mine who has a few rifles took me out in his woods to shoot bottles. He was laughing and picking on me because I was so excited to "finally shoot a real gun" and he was saying how it wasn't much of a big deal. Anyway, he tried showing me what to do, but I said, "don't worry man, I think I know." He laughed and sarcastically agreed and let me try.
I immediately hit all three bottles he had lined up about 200 feet away. Pop! Pop! Pop! Just as easy as in the games.
My point is, I think FPSs have been slowly training us for years for that when SHTF we'll have a chance to fight back.