English joke 长一点的,难一点的

Mr.Smith was a traveling salesman and frequent flyer,so he was always very,VERY careful to mark his luggage so that no one would mistakenly take his bags.He always did this with brightly coloured ribbons and tape,so on one trip as he got to the luggage carousel he was very surprised to see his bags being grabbed by a well dressed man.Mr.Smith walked over to the guy and pointed out the coloured ribbons tied to the handle,and the fluorescent tape on the sides of the bags."I believe that those bags are mine.Were yours marked like this?" he asked."Actually," the man replied,"I was wondering who did this to my luggage."