Bellatrix LeStrange Is a Whimp?

Okay.

This post is going to focus on the Battle at the Ministry of Magic in Harry Potter and the Order of the Phoenix.

In the book, Bellatrix is super demented and insane.
     Duh.
     We know this stuff already.

But why is there a difference in the portrayal of Bellatrix in the book than in the movie.

Bellatrix kills Sirius. Lupin holds Harry back. Harry chases down Bellatrix and uses the Cruciotus Curse on her.
     In the book, Bella laughs her head off, cackling maniacally. She is barely tickled by the curse because Harry didn't mean the curse enough for it to work. She challenges him, enticing him to strike again because the first attempt was just sad. And she knows he can't do it, so why not tick him off more?
     In the movie, however, Harry hits her with the spell once and Bellatrix falls to the ground, pouting and looking like she is about to cry. Can anyone say -- mischaracterization of character? I know I can. That just isn't true to the book or character. I have no idea what they were thinking. Idiots.

Oh well.

Book Bella wins. And that's all that matters.