where a person's paying by card in a shop and it gets declined, and instead of just being a sound human-being they get ridiculously defensive, ask the shop keeper to try again, then either mention that there's a fair deal of money in the account, or blame the machine.

fucking cretins. just apologise, even if it isn't your fault, put the stuff back and go. the world isn't judging you a fucking grim, worthles, live-by-the-day cunt. shit happens.