Why oh why does Hollywood

Why oh why does Hollywood insist on adapting a book for film and twisting in such a manner that the original work is barely discernable in the end product? I always thought books were made into movies because they contained certain compelling plot elements that transferred well to screen, e.g. dramatic espionage involving Russians, romance involving girl who falls for guy who doesn't like girl but does in the end, etc. etc. What's the point of taking the title, the names of the characters, and the vaguest general premise of a book and turning it into a film "based on the book"? I read Girl, Interrupted last fall and found it both disturbing and fascinating at the same time. And while I can say I found the film disturbing, I'd hardly call it fascinating. And it was just plain irritating to me that almost nothing that happened in the book happened in the movie. Nothing. I mean, yeah, in the book the girl goes crazy and is sent to a hospital, in the movie the girl goes crazy and is sent to the hospital. That's it. I don't get it. Do Hollywood writers have a really hard time coming up with titles and character names, so they steal those from books, then use their creative powers to fill in the details? Grrr…The Perfect Storm better be better or I'll be upset. Not only did I read the book, but I remember the storm itself, vividly. I remember walking across the campus at school the next day and staring in amazement at all the downed trees. Huge branches were strewn about everywhere. And I remember reading on the front page of the Boston Globe that a fishing boat from Gloucester was feared lost.