A cowboy rides into town, ties up his horse outside the saloon, walks in and orders a shot of whiskey.
He downs it and walks out.
He notices that his horse has gone so he goes back into the saloon, orders another whiskey and says "If my horse isn't returned by the time I've finished another drink the same thing will happen here as happened in Dodge City.
Now, give me another shot of whiskey." He downs his drink and walks slowly out of the saloon;
his horse is tied up at the rail again.
Just as he is mounting to ride off, the barman come outside and asks "What did happen in Dodge City?"
The cowboy replies "I had to walk home."