Want to have more fun?
You already know about the ridiculous interpretation of the rules that you can't see someone who hid who is walking straight towards you in the open.
Believe it or not, there's a line in the DMG that supports that interpretation.
So, give me a monster with (say) a passive Perception of 9 and a Perception check of -1. The rogue has rolled a 20 on their Stealth check to become invisible (hidden).
Here's the line in the DMG:
"Noticing a hidden creature is never trivially easy or automatically impossible"
You thought noticing the "hidden" creature walking right towards you was trivially easy? Wrong!