I personally hate these:
Ankha - ugly and her eyes are weird
Monique - she looks like a cheap skank
Olivia - something about her rubs me the wrong way
Truffles - my arch enemy
Tammi - my other enemy
I don't really like any of the dogs, tigers, or mice and I actively dislike all of the hamsters and gorillas.
I don't like Paula - her blue eyeshadow and bright yellow hair is really unpleasant against her slightly olive-tinged fur.
I don't like Pudge because he appears to be in perpetual pain.
I don't like Barold, because his features overall are pretty thuggish and grotesque.
I dislike Moe perhaps most of all, his enormous eyes and strange mouth are just unappealing to me.
I don't like Stinky because his name and design in tandem is just gross.
I don't like Roscoe because his eyes are impossibly large.
I don't like Sylvia because her design is just lazy and sloppy, and her color scheme is poorly chosen.
I absolutely loathe Rizzo and Moose and Limberg.
I could list many more... I'm pretty picky about my villagers, haha. Oddly, though, many of my favorites are widely disliked - I love Tiffany, Diva and Gloria, they're among my all-time favorites.
I don't like Al because he stole my birthday. >=(
I don't like Willow that much. She's really cute, but she was quite the issue for many of my villagers in City Folk. Blah.
And I absolutely CANNOT stand Portia. She was so bitter in City Folk, was so happy when she left. Plus her eyes scare me.
Barold will forever be my worst nemesis ever, omg. He is probably the ugliest animal in the game. Hippeaux, Chops, Tabby, Katt, and Truffles are potential run-ups.
ANKHA - GIVE ME BACK MY CLEOPATRA OUTFIT BECAUSE IT'S UGLY ON YOU!
Otherwise..... I dislike a few characters (barold and the anteaters mostly.) and I like most of them.
There are very few that I love and would never let leave my town.
Me too! Took me forever to get rid of Pietro, I almost reset my town because i didnt like him and he just would not leave. I was so happy when he was gone