On Halloween a couple of years ago I saw a video of a teen girl (maybe 15/16) who was half jokingly complaining that she hadn't been able to persuade her friends to join her in scaring little kids (trick or treaters) that evening, by making spooky noises and half heartedly chasing them. WIBU to find this funny, even though it's mean and I wouldn't actually encourage it?
YABU - the girl was mean
YANBU - it would be harmless fun