Even bad people had some good sayings. What's a quote from a "bad person" in the world history that made you at least pause and think?

No one likes to think there is any kind of agreement between them and a "bad person", but the truth is, people aren't black and white. Even evil people can have some good in them or have some sort of point or logic. Focusing on the most evil (dictators, serial killers, and those types of people), can you think of any quote?