I completely agree with OP, I really don't like cows or the bulls, but I think the rhinos are really weird-looking. I had Tank in my town and I started trying to get him to move out the moment he moved in. I had to design a pattern with a picture of him in it but the person I was designing it for wanted everyone to be facing forward and it was impossible to make him look right facing forward. (She refused to pay me by the way!)
Anteaters, bulls, monkeys... not a big fan. There are some exceptions however.
But the worst of all are GORILLAS. Luckily I never had one in game - hope it will never happen.
I never liked the looks of Gorillas but then I got Boone and the sweet loveable lugg stole my heart. For myself the least favorite are the monkeys. Not a fan.