No one in the book Charlotte's Web seems to like Templeton. all of the farm animals say that he is really bad and selfish. Even when Wilbur comes to the barn, since everyone already disslikes him, Wilbur starts to disslike him as well.
I think that everyone says that Templeton is evil because, that's the image that he is getting accross. I believe that it's all just an act, maybe its not even the real Templeton. Every children's book has sort of a villain involved in the story, and Templeton just so happens to be this 'villian.'
But, even though templeton is 'evil' I still think that this bad guy thing is just kind of like a mask, or just the kind of person he wants people to think he is, so they won't bother him, or get in his way. Templeton isn't bad, he just has strange habits.
Since he is not very welcomed by the humans at Zuckerman's farm, he has to find a way to survive because, they don't feed every day like they do to all the other animals, he has to search for his own food, and take advantage of the times when Wilbur isn't going to eat the food that is served to him.
All of the other animals see this, and to them, his habits seem strange, and when someone doesn't understand something, or someone, they label them as bad, mean, evil, wierd, strange, etc etc. thats why I think everyone at the farm doesnt like Templeton. He's not mean, just different (and a bit selfish, but so is everyone so it just makes him seem more human).
