Hermione: Her intelligence is attractive to me but she's bossy so that annoys me while I'm reading the book. She has the whole "I told you so" and "I'm always right" thing going on there. There is just something about her character that I don't like but I can't tell what it is.
Harry: I kind of like his personality but I don't like his occasional arrogance, he usually has no sense at all, and his character can be a straight up ass.
Ron: Senseless, Naive, and once again that indefinable dislike. I do however, like his sarcastic sense of humor.
Tom Riddle: I think a lot of it had to do with the traits he inherited from his parents, his fear of death probably comes from his mother dying and leaving him in the orphanage he despises. His hatred for muggles probably comes from his father leaving his mother and never coming to find him.
Albus: I don't like how he manipulates people to get what he wants even if it is for a good reason.