Gloom:
White spells cost 3 more mana to cast. White encantments with activation costs require 3 more mana to use.
Ahh, the power of Gloom. While my pitiful white opponent devotes every turn to discarding all his powerful creatures and enchantments, I devote every turn to changing another one of his plains into swamps with my Cursed Land card. Even if a disenchant surfaces and somehow he's got enough mana to cast it, I just lay down one of my reserve glooms next turn. He doesn't stand a chance against me. So black decks everywhere, I decree: do not succumb to those faint inclinations of mercy and kindness, no! Spinelessly stockpile those global enchantments and show your pathetic white-deck wielding friend what MTG is all about.