In chess, perhaps in other games also, the concept of touch move is that if you touch a peice you must move it. This is important in chess because it limits distraction for the other player. It is also annoying because if you're impatient, touch a peice and then realize mid grab you missed something it's normally to late and you must move the wrong piece. In tournament chess when you touch a piece that you are unable to move because it would put you in check there is normally a time penalty and your opponent glares at you as though it pains him/her to be playing such an idiot.