I agree with the wallbang's. It's a really big factor in the game, lets say you see a person just before he goes behind a wall or something, you have two options, to wait and think of where he is going/waiting for him to peek), OR you can try to wallbang the guy. If you can't wallbang, the game is basically just waiting for the enemy to peek or waiting for him to come from somewhere else. Also wallbangs add more to the game including skill based factors. PS. sorry for my english not native speaker.