Nietzsche wrote a lot about how people make decisions about how they live their lives. He attacked most of the moral ideas that were popular at the time because he did not believe that there are any real facts about what is right or wrong. He thought people should create their own facts about morality.
He also often attacked the ideas of the Christian religion. He believed that the Christian idea that one should feel pity when one sees weakness was unhelpful. According to him, weak people rely on other people's love as a way of protecting themselves. Nietzsche believed that people should be stronger than that.
FUN FACT:
Nietzsche thought that human beings would be successful at overcoming themselves, and he thought that when they did, they would be different and better. He named the person who would do this someday a "superman".
Adolf Hitler, the German Chancellor and leader of the Nazis in World War II, read Nietzsche's work. Some people say that Hitler did not understand Nietzsche's ideas, but he used them to try to show that his actions were right. Hitler and Benito Mussolini used the term "übermensch" to refer to the Aryan race. However he was not popular among all fascists.