For me it is cats.. I just don't like them. Anything that has 4 legs needs to go to the bathroom outside. End of discussion. No, I don't care that they go in a litter box.. you still have to clean it up.. it might as well be a diaper. And I change enough of those for my son. At least he will one day be potty trained and in the mean time we have a diaper genie to contain the smell. Cats just do their business in a glorified open top cardboard box. gross.
I also don't like that they hiss and scratch and they have beady little eyes. AND the fact that they climb all over everything.. cats on the kitchen counter? hello unsanitary.
and let's all be honest here.. they don't do anything.. you can't take them for a walk or a run.. you can't play fetch with them.. they don't sit, shake, or roll over.
No I haven't ever had a true bad expeirence revolving around cats.. and even my in-laws and my best friend own cats.. doesn't matter.
Basically DOGS > CATS. and in my house:
There are other things I don't do.. but those are posts for another day.. but in true preview style.. children's clothing with characters on them.. and yes there are some exceptions.