Mine would be Bella. She moved in from my brother's pool by accident a few months back, and I've been trying to get rid of her ever since. I stopped playing for a few months and I was kinda hoping she would be gone when I came back, but no luck.
Bree for me as well, along with Pompom. I don't really get it, because they are very cute to me and very sweet. Nobody likes Jitters, either, but he's a good bud of mine.
Hans, Spork, Cyrano, Astrid, Baabara - according to the list on this forum. I'm probably eventually getting rid of all of them except Baabara and maybe Astrid.
eugh curly. WHY WON'T YOU LEAVE? he is so annoying. i usually like my villagers and don't go through a lot of them but man, that pig is annoying (although i have to admit jock personality is probably my least favourite.)
didn't help matters when adorable little crackle moved into my village who is a little sweetie compared to that annoying idiot that is curly.
the icing on the cake had to be when he pinged me telling me he was moving out (finally) couldn't reply quick enough to say cheerio (seriously, go away). he then informed me that my positive reaction to him leaving must mean that i planned on doing no exercise since he wouldn't be there for any training (what?) and he couldn't let that happen, so he stayed.
eugh.
edit: got so angry i forgot to mention curly is my least popular villager according to the list, well deserved too.
I like all my guys! None of them are unpopular in my eyes.
Barold and Gayle I think are bottom tier, which as someone previously said is kinda unfair to Gayle because she's pretty cute with all the pink and hearts and lovely furniture. I'm not sure where Kitty and Merry stand but they're cats so they can't be that bad, and I think Fuchsia was low tier but not bottom? She's leaving anyway though so she won't count for much longer.
(And then I've got Rudy, Wolfgang and ~*~omg marshal~*~ to balance it out. People keep coming round for signatures and then saying "omg marshal" and asking if they can have him when he leaves. LOL)