"Go to the eleventh floor," his friend instructed. "Find apartment G and push the buzzer with your elbow, and when the door opens, quickly put your foot against it."
"Why such an elaborate plan, just to get into your place?" asked the salesman.
"Well," exclaimed the host, "you're not planning on coming empty handed now are you?"
Moral of the story. True sales professionals pay close attention to social convention. If invited somewhere to a party it's customary to bring a fine bottle of wine, or a dessert, or if it's a special occasion, a gift. Failure to do so, could result with you spending a lot more time in front of your computer at home on weekends. With nothing to do but wait for the phone to ring.
"There is a kind of courtesy in skepticism. It would be an offense against polite conventions to press our doubts too far."