A bad switch will simply put contacts together at the same rate as the human pressing it, so it's very random and variable as you press with different strength

A bad switch will simply put contacts together at the same rate as the human pressing it, so it's very random and variable as you press with different strength and speed. A good switch will decouple your finger from the contact by some nonlinear/bistable linkage, so once you accumulate a fixed amount of travel distance it will snap the contacts with the same speed/force. But of course even that isn't perfectly decoupled nor perfectly deterministic.