You're about halfway finished to teaching all those essential life-lessons never learned.
Ya meany.
(harumpt)
edit:
Sorry I was being facetious. Ya wasen't teaching him anything except how to be rude. I would have walked up to the counter and blocked you out if that was me. That happens sometimes when I feel breath on the back of my neck in a supermarket line. My head itches and the elbows get a bit careless. BTW that is less than the three foot rule. So many times I've bagged my own groceries and returned to pay, but find someone already blocking out the point of sale machine, twitching like a junky and breathing heavy. Geeze they must have sprinted through the entire supermarket to need to save that much time.
First mistake gets a courteous "excuse me but". Everyone is owed that.
Only the second time gets the pimp hand.