It doesn't have to be interesting, just tell me something. However, if it is interesting then that would be interesting. Try not to make it something that everyone will have done. I want to hear a wide range of things.
My thing - I had an argument with some jobsworth bitch who works in the café, because she tried to play manager.She told me not to eat my sandwich in the café (but we're supposed to take our breaks there, because we don't have a staff room) and said I had to go and eat in the swimming pool seating area. I told her it was stupid, because the whole point of our breaks are so we can be away from the heat of the swimming pool hall. She ran to the duty manager and made a big fuss, he was spineless and caved in (even though he knew I was right as he later told me) so I said she was a fucking joke and walked off. She then told the centre manager what I said to her. I expect to hear from him shortly I'd imagine, but I'm not worried as she was quite rude to me and I can say I can blame my sudden outburst on tourettes (which will be quite naughty of me if I say, but I don't want to let her win) and then walk off with a happy smiley face.
Bottom line - she's a cunt.