Awful Book-to-Movie Adaptation (WG)

This week's Weekly Geek question asks:

Worst movie adaptations: The recent release of Watchmen based on the graphic novel by Alan Moore got me thinking about what I thought were the worst movie adaptations of books. What book or books did a director or directors completely ruin in the adaptation(s) that you wish you could "unsee," and why in your opinion, what made it or them so bad in contrast to the book or books?

Immediately Starship Troopers came to mind.  In college I took a Science Fiction class because it's never been a genre that I've been terribly fond of.  For my outside readings I focused on the works of Heinlein. (I chose him because of Friday - very few SF authors of the time wrote female protagonists; Heinlein was an exception). So, here I was maybe a junior in college, I just finished reading Starship Troopers and decided to rent the DVD. 

 I might have even been working on a paper where I was going to compare the two (?).  

Dear god, I cringe thinking about that movie again.  And the thing is, I know that S. Troopers has somewhat of a cult-like following for those B flick movie fanatics and that's great.  Good for them.  I'm in favor of the random B-flick movies (Troma! for one)...but I had different expectations for Starship Troopers.  I didn't expect to have the desire to turn it into a MST3K experience.