I think my least favorite species is probably the kangaroo. I just... everything about them. From the creepy babies they carry to their weird blocky shape uGH. Chickens are probably a close second.
I really don't like any of the rabbits. I thought there would be at least one I'd like to have, but nope, I don't find any of them appealing. The kangaroos just have awkward models in general that I can't possibly bring myself to accept.
Poor gorillas though. I thought Boone and Peewee were pretty cute and I felt kinda sad when they moved away. :c
They are getting a lot of hate, but... gorillas are terrible! >_< They really creep me out. And the song that plays when you talk to them just sounds awful. I've never liked them... Hippos or anteaters are probably a really close second though.