But you outlined exactly why she
should act that way while he doesn't.
People act very differently when they know why something is happening as opposed to when they are clueless.
I'm by no means trying to argue that Kristin Kreuk is a good actress (because frankly, I don't) but the dialogue makes sense from the standpoint of natural human reactions.
Look at it from her perspective, though. Everyone knew that she was under the spell of the Nicodemus (sp?) flower or possessed by Thoreau (sp?) whereas Clark is on his red kryptonite trip and no one knows he's infected by anything (other than Chloe and his parents) so why
would she believe that he
isn't just being a complete asshat? She has no reason to believe his actions are the result of anything other than his own personality.
