Hate book to film adaptations and real life things that create new characters.
Then when film crew make historical films, get the things correct. Classic film gaffes are like driving a car which was made 20 years after the time the film was set, using modern day terms, having a film poster in background which was released in the 70s, not in the 60s when film was based.
One classic mistake is in the King’s Speech. Film is based over several years yet the Princesses Elizabeth and Margaret stay the same!