After three and a half months of trying, the labyrinthine rules of etiquette at my local supermarket remain way beyond my simple understanding.
In the absence of a conveyor belt at the checkout, the cashiers stand in a row behind waist-high counters, with the till displays hidden beyond walls of chocolate bars, breath mints, condoms and chewing gum. You put your basket in an angled slot which takes up half of the space between you and the cashier. Sometimes she tells you to leave your things in the basket, sometimes she tells you to take everything out, and sometimes she doesn't bother to tell you anything at all and just points or tuts instead. Whichever option you choose will invariably be the exact opposite of what she wants you to do.
"Do you want a bag?" is always the first question they'll ask. "Do you have a discount card?" the second. The third always used to be, "Don't you have the right change?" but they've stopped asking that one recently - perhaps because they've sussed I'm a foreigner and probably won't understand. Whatever else you do, don't forget to pick up your basket and receipt. You'll be shouted at if you forget the first and stopped at the exit by a guy in a bouncer's uniform if you don't have the second. Unless you're very lucky, any attempt at social niceties will be met with icy silence. Bringing your own bag merits a look of contempt.