No way the most embarrassing for myself, but definitely was a bit for the other person.
I was in the shop taking a shit in the bathroom, (it's a one person bathroom with the toilet basically set in front of the door.) So, anyways, I'm sitting there taking a shit, and a co-worker opens up the door and sees me sitting there, pooping up a storm. I didn't startle or move when he opened the door, and yelled surprise as we made eye contact. That was classic shit. Literally. He was pretty startled. haha.