I was in a hurry to get to the store and back in time for Mincha but I couldn't resist stopping to give a 30-second Jewish-Survival class to a couple of Birthright boys. A large group of Birthright kids were waiting in the Rova (Quarter) Square for their tour to continue. I picked one who really looked Jewish.
"Where're you from?"
"Where in America?"
His mouth dropped open.
"Yeah!" With a look of, "How'd you know?"
He didn't know that Torrey Pines is the only place in San Diego I remember.
"Your mother gave me a message for you."
His mouth dropped open even wider... wondering, "Is this guy for real?"
Pointing and waving my finger at him, with a loud voice I said, "She said that you better marry a Jewish girl or she's going to break both your legs!"
They both cracked up laughing loudly.
And I walked on to the store without looking back.
Now, what do you think happened? They were not used to such an unusual thing as a grey bearded religious looking Jewish man jumping into their conversation to warn them that they have to marry Jewish girls. I guess most people aren't. But I've found that these encounters are surprisingly effective. I have heard from some of my "customers" many years later that for some reason, "It got to me."
They learned that marrying a Jew is the most important thing in the world, at least to this "old guy" it was, or else he would have yelled about something else.