Probably sex, for me.
I’d just do it with someone who wasn’t who I originally did it with because she wasn’t great in bed. The entire moment itself was just embarrassing for the both of us, moreso for me because of the time it last for which wasn’t long and just her seemingly doing it to get it out of the way. There was no passion in it, it was just a matter of “oh lets get you not a virgin anymore” deal and I felt it was tainted.
Ah dude I feel that so much with looking at pond samples under the microscope. It was and still is quite magical, but you can’t beat seeing it for the first time. Just a whole other world right there.