Movies have to live on the surface most of the time because they can't reveal our interior mental life well. Novels and short stories can move in and out of the objective and subjective realms with ease and believabilitiy, but movies tend to look a little goofy when they try that. Even when movies can achieve some depth by overcoming the third person constraint, the limits of time encourage shallowness too. The average movie length is 110 minutes, and you just can't get that much done in that time. It takes history and careful detail to reveal character.
Public speakers know that very few text pages go into an single hour's lecture.
You certainly can't finish a book in that time. That's why most books do poorly as movies. Movies have to leave out too much emotional history. Movies want to ascend to the level of an epic novel, but that's cheating the movie. It's not designed for that sort of feat, and it shouldn't try.