My most recent incidents were last year when I was first breaking my mare. One day we were just riding along through a field. Well, she has an....issue with white flowers. She's convinced they are out to destroy her. So she was having a 'stand off' with such a flower, and as I finally convinced her to keep going past it she farted. She spooked at her own fart and took off at warp-speed across the field.
Then one day we were riding along and came across a little creek -one she could easily step across or through- well, she decided that she'd much rather show me her grand prix jumper impersonation. Launched herself straight up in the air and over it as high as possible, caught my bra on the horn.
Before that was possibly the worst embarrassing incident, I'd just gotten an old freebie appaloosa mare, and my friend who delivered her said "Hey, why don't you come with me to the arena to work cows and try her out?" Yes, I was such a genius and agreed to take a horse I'd never ridden before to a busy arena to work cattle.
The other thing was, I'd never worked cattle before. Nobody bothered to explain to me how the team-sorting thing was supposed to work either. I'm not sure if that's really what it was called, but you had a team of 3, two people waited behind the line to block wrong numbered cows and the third person went into the herd, cut out the right cow and drove it to the line, then the next and so on.
Well, while we were waiting along the side of the arena for our turn, April (the mare) goes about grabbing the person next to me by the leg and dragging them off their horse. I got her away from the others and then, when our turn came, of course I was picked to be the person to go down to the herd and cut the cows.
My fat little old mare had other plans. She stopped, wouldn't move. Right in front of the herd. After almost running out of time she finally super slowly moves through the herd, we get the cow, and at this point she finally decides to be 'cowy'. As the cow tried to turn back to the herd she whipped around so fast I flew half on her. She calmly walked back to the front of the arena with me hanging off her side with my arms around my neck hanging for dear life.
After we were done working cows I decided to get on her bareback, only she was so round that as I jumped up I slid right over her other side and landed on the ground right in front of everyone. (I have yet to live any of those down xD)