Chicken or Egg?

Which is better to do first: read the book, or watch the movie?

This is the downright dumbest excuse for a fundamental question I've ever had, but here it is. I want to know what you think is better.

Everyone knows by now that if you read the book first, you'll spend the majority of the movie thinking to yourself (or shouting out loud, if you're the type), "Dude, that's not what's supposed to happen!" or "She's supposed to go in the building FIRST!" or "What happened to all the other characters?" or "This doesn't even resemble the central plot of the book. It's like they took all the same characters and wrote a new story for them."

You find yourself unable to enjoy the film for itself, because in your mind it should be the visual companion to the book you know and love, when in fact almost no movie can accomplish such a feat without being 11 hours long. Producers, screenwriters, editors, etc. simply have to change a story, to chop it up and strip it down to bare essentials simply for time constraints. "But, but, no, don't you think maybe..." No. Maybe with the DVD they can recut it and add in all that extra footage (a la Lord of the Rings and Stargate) and make it more like the book, but the theatrical release has to be shortened. It's not like we have intermission these days. People gotta pee. Shorten the story so I can go pee!

This does not mean, however, that I approve of some screenwriters' habit of taking the main characters and just giving them completely new plots. Most of the time I get all pissy and feel like demanding a refund. If I wanted to see Princess Mia Fights the Custom of Marriage while Receiving Gentle Advice from Julie Andrews, I'd write a piece of crappy Princess Diaries fanfiction. I like my Princess Mia the Smartalecky Teenage New Yorker with the Grandmother from Hell, just the way Meg Cabot wrote it.

Do you see what I mean? These movies are good in and of themselves, but I can't just sit and watch these movies and enjoy them for what they are now that I've read the books. In my mind, Mia's Grandmother should be a princess, not a queen, and she should have eyeliner tattooed to her lids, a balding toy poodle, and a prediliction for Sidecars (1/3 lemon juice, 1/3 Cointreau, 1/3 brandy shaken well with ice, strained before serving). Fitzwilliam Darcy should not have that stupid look on his face as though someone were trying to teach him Einstein's theory of relativity 140 years too early. Harry Freaking Potter should have...oh, I won't go there.

On the other hand...

Yesterday I finished reading Practical Magic. Do you recall that film, with Nicole Kidman and Sandra Bullock? Can you picture Gillian (Kidman) with her long red hair? Can you see the children casting spells? Remember the aunts casting an attraction spell on Sally (Bullock)? Can you picture that hot cop (played by Aidan Quinn) with the multi-colored eyes? That's nice, but don't expect to find them in the book in that way.

Gillian has short blond hair and falls in love with a biology teacher. The children are surly teenagers who don't even know their aunts are witches, and they certainly don't cast their own spells. The hot cop has brown eyes, and he did not come as the result of that cute little spell Sally cast when she was a kid (the spell never happened).

This is not a big deal, really. It's clear the screenwriter took the story and did some major changes, but that's not what bothers me most. No, the problem is that when I read, I can only picture Bullock, Kidman, and Quinn in those roles. And the aunts? Yeah, I can only see Stockard Channing and Dianne Weist. My imagination has been limited, because I saw the movie first. I should be sitting there picturing a blonde in her mid thirties, but all I can come up with is Nicole in her twenties. I should be making up my own ideas about the clothes, scenery, houses, minor characters, etc. But I'm stuck in the movie. I'm stuck with those actors, those set directors, costumers, etc. And if there's one thing I can't stand, it's having someone else limit my imagination for me.

So, back to my question. What's better? Book first, or movie first?