Socrates
Socrates helped  people to see what was wrong with their ideas. Sometimes they liked this, sometimes they were not happy or grateful. He said that he, Socrates, was not wise, but that he "knew that he knew nothing." Since other people think they know something, but no one really knows anything, Socrates claimed he knew more than anyone else. He said that people who do bad things do so because they do not know any better.