I’ll go first:
First day of highschool, slipped and fell in a puddle of vomit, and some kids laughed. Sheepishly went to the bathroom and rinsed my uniform, and put it in my bag. Spent the rest of the day in gym clothes which I luckily had that day, still smelling like vomit though.
Good thing when you don’t know anyone yet is nobody remembers.
I once told an embarrassing story on a public forum.