6. D.W. Read (Arthur)
Arthur's younger sister always struck me as some sort of deluded, preschool sociopath. In the very opening titles, her exclamation of indignant surprise was the reason Arthur could have fallen to his death (actually, there's something - is the whole Arthur TV series just D.W. hallucinating whilst watching television? Someone get Christopher Nolan on the phone..!) Because let's face it, D.W. hallucinated - she wasn't 'all there'. Her only friend was a flaky imaginary creature that looks like the lovechild of a ball of lint and a squirrel, and her interactions with Timmy and Tommy Tibble showed that she's passive aggressive, and incredibly selfish. But the thing that really pushes her into psychotic territory for me is the fact that she always seemed to have this burning, irrational hatred for the Read family puppy, Pal. A puppy.
A puppy?! I can understand sometimes becoming exasperated with an animal, but outright loathing it, unprovoked? That's insane! Throw in the fact that D.W. found it perfectly acceptable to walk around in knee high socks on a daily basis, and you've basically got the classic profile of a psychopath