My favorite overheard undergrad story:

I was walking past the lecture hall right after an organic chemistry midterm, and there was a cluster of 4-5 students talking about the exam. One asked about question 8b, and another one said “you’re not supposed to mix nitric acid and ethanol, that makes TNT, right?” I had to stifle a chuckle as I walked by.

So close, and yet so far! Nitrated acetone is explosive, and TNT (trinitrotoluene) is also made with nitric acid, but toluene is a much more complex molecule than acetone. If those undergrads could figure out how to turn acetone into TNT efficiently, they’d get a Nobel!