Ok, so I've noticed a Wikia Contributor has literally said that Shannon is stupid and a horrible person. While this may be your opinion, let me explain why I do not think this is so. Shannon, from what is implied in Wolfsbane, misunderstood to the point where her parents are considering sending her to a psychiatric. This is not to be taken lightly, and we can see from her childhood that what's she had to grow up around has not been the best environment. As a child, she saw something unbelievable, and because of that, it became an interest to her. When all the other kids were calling her weird, it may've just fuelled that desire to find the beast, because then at least she could say, ha, I told you so. So when her friend shows signs of being that beast that ruined everything for her
NATURALLY SHE'S GOING TO TRY AND PROVE THAT IT'S HER
Because this thing, for her whole life virtually, has haunted her, and to have her best friend, the one person she trusts more than anyone in the world, possibly be the thing that ruined her life, well then it is just more motivation to try and prove this, and this is why I feel so bad for her in Dark Moon, because this is literally a turning point for her, because she's almost given up, because she is almost starting to accept that maybe she's crazy. I don't know, these are just a random collection of my thoughts, but tell me what you think in the comments.