Five engineers and five salespeople move to a salon. Each of the 5 salesmen will buy a train ticket. Engineers only buy ONE ticket. The engineers will lock themselves in the toilet just before the controller arrives. By the way, the controller sees that the toilets are occupied. He knocks on the door and asks
" Your ticket please! ".
Engineers slip the ticket under the door. The controller is satisfied and goes away. The Salespeople are upset that the engineers have once again taught them. For the return, the 5 salespeople buy ONE ticket. As for the engineers, they do not buy NO tickets. The 5 salespeople lock themselves in the toilet just before the controller arrives. The Engineers discreetly pass by, knock on the door and ask
" Your ticket please! And take refuge in the toilets next door ... ..
Morality: salespeople always try to apply engineering techniques without ever really understanding them.