Joining the current trend.
I'm a cat and dog person. I've had 3 cats, first one being a deranged tabby (Norwegian forest cat) who used whatever she wanted as a toilet. Favorites were beds, rugs and sinks. Second one was her kitten, same breed and a fantastic cat. Good understanding of language too. She would say good morning to you and be offended if you didn't answer. Some cats prefer not to be petted too long, mostly since it hinders them form sleeping. She was one of them, but there was mutual respect. She knew perfectly well that she was screwed if she didn't obey the rules.
At the moment though, we've got a Siamese. (On my lap right now actually). Took a while to train her as her first owners let her walk on the tables and fed her with tubed cheese

If you didn't remember to put the food away, she would take it. One time she devoured half a chicken and then took the other one by the leg running for cover. She would be busted pretty easily as she sings as she eats. It's amazing how well she understands language though. She'll want something specific and if you ask her what it is she can actually show you. A lot of verbal communication compared to other cats.
As for the dog, I've got a Border Collie. She understands language so well she makes schemes. If you don't pet her, she'll just go over to the next person and look at you like you've missed out. If you say the word "pants", she'll allready be halfway to the front door as she's figured out that a change of clothes means a walk. When you're walking around the house, she'll place a football just out of sight so you'll kick it when you walk past. She had puppies this summer, so I've raised the two from the ground up. Just visited them at their new home. They have acquired
superspeed. So yeah...

<- I keep thinking brown slime/booger things when I see these for some reason.