This one is something that I saw, but it was definitely my fault.

One day I was commuting across town with my trailer in tow. I had stopped a red light with the intention of turning left. This intersection is a 2 lane + turn lane each way, and it's always stuffed full of cars, so at minimum there were 12 cars watching me. The arrow turned green and I started making my way across the intersection. About halfway through I made the observation "man, I must be getting stronger because it doesn't feel like I'm pulling the trailer at all." At that moment, I looked to my right to see the trailer heading straight down the road across the intersection and subsequently down the slight hill on the other side of it. I had to make the U-turn of shame onto the sidewalk to make my way back and get it, all while grinning from ear to ear (because it was a hilarious situation.)

I'd imagine I entertained a few people at the red light that day. I had to tie the trailer to my bike with a shoelace to get it home.