Here's another one

.
This one is by Richard Prior, i believe (now I ain't gonna get allll the details exactly right, but it'll be funny anyway).
He said, that there was always this big ferocious dog in the neighbor hood that would always chase him when he was a post man. Every single day, he'd hear the barking and then see the dog. Every single day he had run for his life for fear of being devoured by the mean dog. One day, though, the dog started barking and running towards him, but he just kept on slowly strolling along like the dog wasn't even there.
The dog stops dead in his tracks and is totally confused

as to why this man ain't running his legs off. The dog stops and looks at him and says, "Hey man. Everyday you come out here and everyday I run after you, buy today, you ain't runnin'. What's wrong with you man?
Richard says, well, I just lost my wife yesterday, dog, and I'm really, very sad.
The dog, slowly turns around and starts to solemnly walk back to his dog house. He's about halfway there when he turns around and says to Richard, "You do know that tomorrow I'm still gonna be chasin' you, right?"
Aaah. I love that one. It's funnier heard in person and I love dogs alot, so it hits me harder than it may hit you.