Witches are often portrayed as having green skin and covered with warts. The reason for this can be traced back to Celtic traditions that associated witches with fairies, since both were thought to be not of this world. In fact, in Britain a fairy or person with psychic abilities was referred to as “greensleeve” or “green jacket.” It was often considered unlucky to wear green clothing because it might incur the wrath of fairies or witches who considered the color their own. Warts are often considered to be caused by witch curses. Since witches dislike witches more powerful than themselves it is considered proof of superiority to have been cursed enough to have many warts.