Why is history imperfect?

History is so imperfect because people believe in different things. Some people will think a person could be a hero and others list things that consider him a villain. People write their side of the story on how they saw it happened. History goes back to billions of years with the fact that people were not there when it happened we have to make predictions and find research to investigate how something possibly could have occurred. With predictions and research this could lead to little and/or false information that may or may not be true.