Comment by IshKebab

I still haven't used K/Q/etc. because they look insane, but the more I read about them the more it seems like they are basically the maths equivalent of regexes. Super terse and powerful. Pretty much write-only. Very useful for interactive use, definitely. But if you find yourself hitting "save" on a regex that's a red flag and if most of your program relies on regexes something has gone very wrong.