As for things i’ve learned and never used? Most all my public school education. The usual stuff like the 3 r’s and typing, mechanical drawing and trig all came in handy later in life, but as is painfully obvious, while i made A’s in english i never paid enough attention to proper use of english to do any more than make grades, then forgot it almost as quickly as i learned it. There were others, chemistry, home economics which i only took because it was required. I already knew how to cook pretty good so i did well in that, but every bit of the rest i pretty much blew off except to maintain grades. I learned without learning if that makes any sense. Whatever it took to keep a 4.0 GPA, but things that didn’t interest me never stuck longer than required to make grades, then bye bye.