A politician gets a phone call from a woman who has a simple message: "I hope you drop dead." There's no way to know who the woman is, or why she wishes he were dead. The incident starts to bother the politician... he keeps finding himself wondering who this woman is. He wishes he could find her and ask her why she wants him dead.
Later, the man again gets the same message from the same woman: "I hope you drop dead." He becomes nervous, and it begins to interfere with his life. He worries about the anonymous voice and wonders when it'll come again. His anxiety preys on him to the point that his doctor tells him that if he doesn't relax it may kill him.
Words can hurt, and in anonymity there is power. One person, acting alone and using only five words, can change someone's life.
I hope you drop dead.