"At Valve, they have a saying:
“If I shoot at a wall, something should happen.”
This is a heuristic they use when designing games. It makes sure that players are able to interact with the world in ways that make sense to them. Bullets shouldn’t just phase through a wall and leave no trace. They should make a raucous ping and leave pitted marks. Action, reaction. Cause, effect. When games fail to respond appropriately, when an action does not yield an appropriate reaction, Newton cringes. And players do too."