>Team Rocket (gen 1)
Steal and sell pokemon, mafia style
>Team Rocket (gen 2)
Revive fallen gang and return to former prestige
>Aqua and Magma
physically change the world to fit perceived ideal
>Team Galactic
create a new, prefect, universe
>Team Plasma
seeked humane treatment of pokemon and wanted a society where people and pokemon could live in peace but actually led by a power hungry shadow council out for world domination
>Team Flare
believed the world had reached the Malthusian catastrophe and sought population control in order to bring stability and balance back to nature
>Team Skull
________________________________________________________________...]________________________________________________________________

Why did they do it? No, seriously.