I have two stories to share. One happened with a couples of out-of-town girls who were in Brooklyn for Shabbos. Passing a couple of Yeshivah Bachurim, one called out, “Good Shabbos!” When she received no response, she called out in a louder voice, “Good Shabbos!!” When there was still no response forthcoming, she called out (now even farther away), “I’M SORRY! I THOUGHT YOU WERE JEWISH!” Note that there was no sarcasm involved.
The second was related to me by an acquaintance of mine. He and his wife have lived in Rechavia for decades. When they first got there, his wife complained to him about the unfriendly feeling that she had there. “With the exception of one old man who always wishes me “Good morning”, everybody just ignores me!” A few days later, she said to her husband, “There’s the man who always greets me!” It was Harav Shlomo Zalman Aurbach ZTZ”L.