Let's call him Bob.
Bob is down on his luck, his wife left him and took the kids. He lost his job, the bank foreclosed and he got evicted from his home. His family were of no help at all. So completely destitute, he has to check in to the hostel for the night with all the other down and outs. He is ordered to take a shower, get deloused, and is issued with a blanket. On arrival in the dormitory, there is only one place free, the lower bunk up in the far corner. Gratefull to have a roof over his head, he settles in, and soon the lights are turned off. Soon a voice from near the other end of the dormitory calls out "Fifty five" and everybody (except Bob) bursts out laughing. After a few minutes the laughter subsides, but soon another voice calls out "seventy six" and the place literally rocks with laughter, everyone, except Bob, are splitting their sides in unrestrained mirth. Completely puzzled, Bob asks the guy in the bunk above him what is going on. "Well young man, a lot of us here know each other a long time, and we all know each other's jokes so well, that to save time we just gave them a number. So when someone calls out a number, we remember the joke and it just comes back to us. Damn funny."
So Bob decides to get in on the action, and after a few more jokes are called out he decides to shout out a number that has not been used yet. "Twenty nine" he shouts, but complete silence follows. He whispers up to the guy above him "Is there no joke N°29 ?"
"Oh yes, and a mighty good one it is too" comes the reply, "but it's all in the way you tell it".