They're meant to be annoying, tricksy creatures that like to trick people and have a weird, indecipherable logic. Therefore, the GM who wants to use Fey in their games and abides by this central conceit will be designing encounters that are annoying and indecipherable, leading to players, predictably, not understanding the encounter and getting annoyed.

This is simply Not Fun.

A player has to understand the rules and mechanics of the game they're playing to be able to make meaningful choices and have agency in the game - this is directly at odds with the Fey's weird, indecipherable logic schtick.

Creatures being annoying is not an engaging, novel or funny concept. They are, in fact, just annoying. This is a problem in a game where you're trying to have fun.

It's been an awesome year and I hope you all are doing well.