Programming.

My shop and CAD teacher in high school singled me out to join his programming class, but he'd got me in trouble for doing stick death art so I was like "f-you man!"

It was such a missed opportunity. I was already programming calculators ... but I didn't realize that was "real" programming until much later. One big lol from my calculator days is I would program without line breaks not realizing they weren't supposed to be like that.