This is more of a funny story (for me) but really gross nonetheless...
A few years ago, my aunt got remarried and had a baby right away with her new husband. She had two teenagers from her previous marriage, both of high school age.
One of her teenagers (my cousin Kristi) was a junior in HS and was getting ready to go to homecoming on the same day that baby Ben had a really nasty case of some kind of stomach thing, which led to horrible diarrhea. So Ben's going through like a diaper every couple hours and my aunt is freaking out because Kristi is being a total brat about homecoming and she's dealing with her sick baby, and her husband is out of town on top of it.
My mom and I went over for homecoming pictures and to help my aunt out and Kristi is sitting there throwing a total temper tantrum -- this girl was seriously bratty, totally popular and totally spoiled by her dad -- about how she's not getting enough attention on homecoming or whatever and my poor aunt is totally fed up. My Aunt yells at Kristi to get off her lazy whiny butt and take out the trash to help her out. Kristi is crying and stomping around and in a huff grabs the trash and takes it outside.
She was walking to the street when her date (meathead football player) pulls up with a bunch of the other kids in the homecoming group. I guess the trash bag wasn't tied well or whatever because at that moment, a diaper slips out of the top and nasty baby poop smears all over Kristi, down her neck, in her hair, and down the front of her dress.
Needless to say, Kristi ended up missing homecoming due to being totally poopy and while the incident didn't really ruin her reputation or anything, she got teased about the incident for the rest of the year. Glad to say that Kristi is a freshman in college now and has ditched the princess attitude and is a really cool girl now, but at the time, I can't say I wasn't laughing.