I read books because I do not find anything meaningful on the television to watch. I was doing my research about Hitler and the epoch that he was involved. I came across General Erich Von Manstein; I bought a book about the general that was written by Benoit Lemay. At some point in the book, the author says that the British Armed Forces were able to run away from the Wehrmacht because Hitler was going through his class conflict with his generals.
Hitler came from the bottom of social stratification and was not well received by his generals that they came from aristocratic families. During the Dunkirk event, Hitler did not allow his soldiers to open fire at the British Armed Forces because he wanted to illustrate to his generals that he was the man in-charge of the army and not them.
Overall, Hollywood is not the source of valid information, but a source of propaganda, pick a book, choose a topic and do your research to expand your horizon.