There was a man who use to rescue old greyhounds from the race track.
One day a visitor to the man asked one of the dogs “Dog, why aren't racing anymore?”
“Did you stop winning?” He asked
“No, I always won.” said the dog
“Was the pay to low” He asked
“No the pay was great” said the dog
“Were you not getting the recognition you wanted” He asked
“No I was really famous” answered the dog
“Well then what, why did you stop racing” He asked
and the dog answered
"Because one day I realised that rabbit I was chasing wasn't real."