Cheng: You OK, Sir?
Shlomo: Air-conditioner! Not-functioning!
Entering the premise, Cheng found nothing wrong and turned it on. Shlomo offered a $10 tip.
Cheng: No need, Sir.
Shlomo: You don’t understand. Today is Sabbath; I’m not allowed to turn-on any machine.
Cheng took the bill. For next four summers, he would spend his Saturday mornings in that neighborhood.