I don't actually do any of these things, I am just proxying for those donkeys that do.
Here's another good one though. Pick a slightly dented can or something flavoured, from the very farthest end of the store, make sure it is the last item through the scanner, then say 'sorry it's dented, could you get someone to change it for me please' or 'sorry I didn't want this in strawberry I really wanted chocolate, could you get someone to change it for me please'. Then on goes the little flashing light at the checkout as it takes endless minutes for someone to run and change it. Why am I always the next person in the queue when this happens ?
ummmmmmmmmmmmmmmmmmmm, switch on the pop-up blocker in your browser, although you might have to selectively allow them for certain sites, internet banking sometimes usus them.