Just that really. During my student days I did a number of crappy customer service jobs to enable me to afford to study (supermarkets, cafes, that type of thing). Now although most members of public are fine, there were definitely some who were ridiculously difficult, or would come up with the most stupid complaints. I was recently reminded of a incident when I was working in a café and we had a special of the day of four cheese pasta, which was under display under the hotplate. A customer ordered a portion which was served to her and she went to eat it at a table. A couple of minutes later she came back to the counter to complain about it. When asked by the manager what was wrong with it she said it was "too cheesy".
What would you expect from a four cheese pasta?
Anyway, since it's cold and I can't be bothered to go out, I thought I'd ask the good people of Mumsnet if you had any more funny examples of times when the customer most definitely hasn't been right to help cheer up my cold afternoon with a slightly grumpy teething baby. 