UPD: Seems I have a better answer - it is computers per se. When I began study of programming I was opinionated on idea to heavily learn system programming - C+

UPD: Seems I have a better answer - it is computers per se. When I began study of programming I was opinionated on idea to heavily learn system programming - C++, Asm, Rust had not been invented by that time, OS theory and things I have already mentioned. Now I hate all I know about computers and prefer interpret languages like JS. I haven't escaped from the needness to know about how a processor treats that binaries, but it is very boring and fast-obsoleting stuff and I wish I could tell myself younger not to bother about computers but rather to grok data types and algos.