With today's payment options by debit you are automatically offered the option of including a tip. Press one, two or three for the amount you choose. I don't buy into that in most cases. I carry a one or two dollar coin for the purpose of quick purchases. There is almost always a tip jar of some sort.
When I drop a coin into the tip jar and get no reaction from the deadhead behind the counter I feel a need to say something appropriate, but that is no longer is satisfactory
I simply reach in and extract my tip, just to witness the reaction from the fool on the dunces face