I have a couple of good ones.
When I was 12 I was spending a day trip at Canobie Lake Park. My older brother and I had decided to ride back row of Yankee Canonball (This was like my fifth time riding this). We were going up the lift hill and right before the first drop, my brother unbuckles my seatbelt! It was completely unexpected. I know this ride and other classic woodies used to just use loose lap bars, and that the seat belts are never tight, but the seat belts really are the only thing that keeps you in your seat on classic woodies! I probably could have quickly buckled it back in, but I was kind of struggling with it and it all happened in two seconds. So I rapped my arms around the lap bar and held on for dear life! Half of me was terrified, but half of me was enjoying it. I sort of ended up half-standing thoughout the rest of the ride.
But overall, I'm actually glad that my brother did that, because the ride ended up being a lot more exciting and fun! Although I'm not sure if I'll ever try something like that again....
The other story was during my big family trip to Cedar Point last year. We were all riding Gemini for the first time, and during the ride I kept high-fiving this guy who was in the other train. Halfway through the ride, on one of the turns, I was going for another high five and the guy- who decided to mess with me- grabbed my arm for a good second! I wasn't mad at him, but my mother- who was in the seat right behind him- saw what happened and screamed, "LET GO OF MY SON!"
It would've been much worse but probably even funnier if the guy did it to some younger kid. But anyway, I think that's all I have.