The Real Evil One In Wizard Of Oz

Every year The Wizard of Oz puts in an appearance around this time but despite watching it a gazillion times, i never really took much notice of just why the Wicked Witch of the West was the baddie and Dorothy the goodie.
Obviously having Wicked in your name is not the best start but as far as i could tell Dorothy landed a house on her sister, the Wicked Witch of the East, and then stole her slippers.
The Wicked Witch of the West never wanted to take them in order to rule the World like a Bond villain, she just wanted the slippers after some stranger had crushed her sibling to death.
Being a Witch, and an evil one to boot, she could have done anything to Dorothy, turned her into a toad, made her break out in boils or even made her head explode but all she did was pine for her sisters slippers.
To top it Dorothy, wearing the slippers like some sort of murder's mad trophy, then kills the Witch which means that in one day, she has not only killed a couple of sisters, one by landing a house on her head, but also stole their footwear so how is she then the goodie and how have i never noticed that before?