I wish their type chart nulified itself. Like, for example, Normal is imune to Ghost, and Ghost to Normal. Fighting is effective against Normal, and Normal against Fighting. Steel and Rock resists Normal, and Normal resists Steel and Rock.
And what about Grass, Fire, and Water?
Grass beats Fire? Fire beats Water? Water beats Grass?
I don't think the type chart needs to nullify itself... just that something needs to beat something... and something needs to resist something... I don't like one-sided rock-paper-scissors match-ups.
Eevee's original Eeveelutions triggered my OCD for that reason. You are presented with the choice of evolving your Eevee into a Fire-type, a Water-type, and an Electric-type.
Electric beats Water.
Water beats Fire.
Fire beats nothing (I know Fire beats Grass, Bug, etc. but that's besides the point)
It was like Jolteon was the best Eeveelution and Flareon was the worst Eeveelution in Red/BlueYellow.
At least the starters were evenly matched... Bulbasaur beats Squirtle. Squirtle beats Charmander. Charmander beats Bulbasaur.