It was a short that ran on Nickelodeon when I was little about two cats. There was a black cat and a gray striped cat, and they pretty much embodied the two stereotypical cat types: the black one was the moody one with an attitude and the gray one was a big doofus. I'd be willing to bet money that it was Canadian, but who can say.
They were normal, everyday cats, and the short had no dialogue and was set to music. It just sort of went through the day as the black cat went along doing normal cat things, and the gray cat innocently caused disaster and screwed things up, angering the black cat. I distinctly remember that every time the black cat got angry there was this shrill, grating sound effect (a lot like feedback on a mike).
Anyway, as the short goes on the black cat just gets angrier and angrier (whiles't the gray cat is oblivious and cheerful). At the very end, the gray cat lays on the black cat or sits on him or something, and the black cat is furious, and you think he's going to attack the gray cat. Then gray cat licks him on the face, and black cat's anger sort of fizzles out, and he's sort of like "oh well" and they fall asleep.
I remember the short distinctly, but I don't have anything I could pinpoint to, say, find it on youtube, or something.
EDIT: Steph wins the prize! The short is "House Cats" by Peg McClure *quietly puts a tic mark in the "California" column*. It is also apparently not up on the internet anywhere.