I do this, try it. At the checkout, you know the way people try to load their shopping up on to the conveyor as soon as that little space appears as it moves forward. Well, don't. When it's your turn, wait. Let the conveyor edge forward, a foot at a time, so there are 2 feet of free space, then 3 feet, but don't load your shopping. You will feel the unrest and anger in the queue behind you. Turn round and smile benignly at them. Don't load your shopping until the very very last minute. A laugh a minute when I go shopping. And I *always* pay cash.