The person who takes every opportunity to "pick on" others is often mistakenly called "sadistic". In reality, this person is a misdirected masochist who is working towards his own destruction. The reason a person viciously strikes out against you is because they are afraid of you or what you represent, or are resentful of your happiness. They are weak, insecure, and on extremely shaky ground when you throw your curse, and they make ideal human sacrifices.
"The Satanic Bible". Book by Anton Szandor LaVey, 1969.