the one i actually liked was "you can switch to a pistol faster than to any other weapon" and i like it because i spray and pray and run out of ammo in a 1v1 too quickly for my own good.
In Modern Warfare 2, in the first mission (the training in the pit), the guy who hands you your weapons goes "Remember, switching to your pistol is always faster than reloading" and the way he says it, that quote stuck with me (and according to google stuck with a lot of people).
He saved me many times while playing online.
He saved me many times while playing online.