A Jewish man named Moshe opened a Kosher restaurant and put a notice in the window: “ARABS NOT WELCOME”
The next day, an Arab walked in and requested a sandwich. Moshe decided that he really didn’t want to risk causing a scene, so he made the Arab the sandwich but charged him double the price.
The next day the same Arab was back, and this time he ordered a full lunch.
Moshe charged him triple and thought, “Maybe he’ll take the hint this time!”
The Arab ate his lunch, paid without a quibble, praised the food and requested a reservation for 10 of his friends for that same evening.
Moshe decided to book the reservation, but to charge them all tenfold!
That evening, the Arabs came and had a very large dinner. They paid without complaining and even tipped generously.
The next day Moshe put a new sign in the window: “JEWS NOT WELCOME.”