Glinda the good witch is the best villain. She lets another witch get crushed by a flying house and then convinces an innocent girl (Dorothy) that it was her fault. When the dead witches sister comes to take the body and give her sister a proper burial, Glinda steals the shoes right from the corpse and forces Dorothy to wear them. Then Glinda puts the blame on Dorothy so that the other witch wants to kill Dorothy. Glinda tells Dorothy that to get home she must see the Wizard of Oz (when Glinda knows Dorothy could easily get home with the shoes), knowing that the wizard would tell Dorothy to kill the witch. After Dorothy kills the witch they figure out that the wizard is a fraud. Then Glinda tells Dorothy how to go home to get rid of her.

Glinda tricked Dorothy into killing the only two other witches and then exposing the only wizard as a fraud, thereby leaving Glinda as the only supreme magical power in all of Oz. It was all just her plan to take over Oz, but what makes her the best villain is that nobody ever suspected she was a villain, she even has the name 'Glinda the good witch'.

tldr: Glinda makes Dorothy kill everything so that Glinda is free to fuck everything.