a joke I heard on the radio

A man walked into a diner and sits down at the counter. He notices an old man a few seats down just starring at his bowl of chili. After about 15 minutes of him starring the guy says "hey if you aren't going to eat that can I have it?" The old man looks at him and says "sure why not." and passes the bowl down. The guy eats the chili and gets almost to the bottom and finds a dead rat and throws it all up back into the bowl. The old man looks over and says "yep that's about how far I got too."