Hong Meirin (IaMP)
WHATEVER YOU DO, DO NOT ATTEMPT TO LEARN HONG MEIRIN FIRST!
Seriously. You run the very real risk of never learning how to properly play the game if you do so. IaMP revolves around two things: projectile-player interaction, and superjump-based pressure.
Trying to play her after you understand how the game engine works is one thing. However, using her as a conduit to learning how the game works is considered to be an error by any IaMP player worth their weight in salt, and may result in permanent damage.
Hong Meirin (also known as Chuugoku) is this games hidden character added solely as fan-service. Fittingly, she is considered the joke character for the entire Touhou fandom). Being a master of master arts, one would expect Chuugoku's projectiles to be poor, offset by some very dangerous and high-damage melee attacks. That is half correct -- her projectiles are very poor indeed (sporting a coverage/spirit cost ratio that is significantly worse than anyone else in the game), but her melee does horrible horrible damage. However, Chuugoku does have some saving grace because her normals all chain into preset sequences, meaning that she has frame traps upon frame traps upon frame traps with her punches and kicks.
Chuugoku is the worst character in the game, and by a fairly wide margin. Picking her is considered an insult in some circles, and may unleash dramabombs upon your opponent.