People behind you in the queue at the supermarket checkout who try and load their shopping on to the conveyor belt when there is not enough room, or who try to shove your shopping further up the conveyor belt to make more room for theirs.
Just wait for the conveyor belt to move forwards for ***** sake.
And then whilst you are trying to pack your shopping away, and pay for it at the same time, they sit tut-tutting about how long you are taking.
Look, I'm not an effing octopus with eight arms, so I can only do one thing at a time.