Yes some of my better friends in high school thought it would be a nice experience for me to sit in Hcl for a period. I must confide that you cannot feel acid on your seat because it does not feel wet. At the end of class I had the distinction of mooning many of my classmates and the teacher. Unfortunately my friends were suspended for a week and I ruined the teachers sweater wearing it on the way home. To great relief my a-- remained whole and still serves me today.

Spontaneous boiling of concentrated sulfuric acid when you add a splash of water gets the heart beating a few chirps!

And thermite labs.

In high school I threw potassium into a sink full of water. It was unexpected from my teacher's point of view, I'm sure I would've been expelled if it weren't for the fact that the school needed my grades for its performance review!

When the Harvard post doc started a big fire?

Usually it's human shit. Like undergrads breaking glass and cutting their hands, or fainting spells, or chemical Burns due to improper technique. Other than that I'm usually pretty careful. One of our interns did set a hood on fire once. My worst was a chloroform spill, after which we had to vent the room for a few hours

Lab accidents? Lol, no unplanned exothermal reactions that I recall, however, I had a professor ignite a hydrogen filled balloon, once. She was planning that, though. With the lights turned low, stadium seating, and her stage, it reminded me of a concert.