Personally despise anybody who, when in the supermarket, gets to the checkout and either:
1. Doesn't pack their items immediately/put them quickly back into their trolley (live in a country where there generally isn't loads of room and the next customer has to wait for person in front of them to be completely finished before your stuff can be scanned through
2. Isn't ready to pay/appears surprised to be asked to pay (generally old women - "That's 35,66 please", cue woman looking shocked and starting to search frantically for her purse).
Or people who start counting out changes for about 50 seconds, only to realise they don't have enough and then take out their card instead, making the transaction last about 3 minutes rather than the 1 minute it should take: "2 pounds, 3 pounds, 4 pounds, 4 pounds twenty, twenty five, six, twenty seven... oh, I don't have enough, I'll pay with the card please." 'Kin idiots.
Also, on a similar note, when there is a massive queue at just one checkout, then another member of staff appears and opens up a second checkout and calls out for people to come over, and people miles behind you leg it over there without a second thought that maybe, just maybe, those people who've been waiting longer should be allowed to go over first.
Also grumpy checkout staff.
I just basically hate German supermarkets, awful awful places.