It always surprised me. That is, the screenwriter read about a certain character and was like, "A character tired of work and funny. I'll make him into a villain who wants to take over the world" or "A sullen man who for the most part feels like the author is conveying his thoughts through him. I'll make a nice guy out of him."
For example, Harry Potter in the first book is a guy who can stand up for himself, a little daring and brave, and in the film a modest and downtrodden boy. I was even surprised when I started reading the book and saw Harry like that.
by mystery5009