The Previous Lubavitcher Rebbe, Rabbi Yosef Yitzchak Schneersohn, once shared an episode from his youth:
When he was seven years old, his mother gave him some watermelon to eat as a snack.
Upon going outside the youngster saw a number of his friends. They all sat down on the benches that were outside of the home and the young, future Rebbe shared his treat with his companions.
His father, the fifth Lubavitcher Rebbe, Rabbi Sholom Dovber, saw the incident from his office window and summoned his son to have a word with him.
The Rebbe told his son as follows:
“I see that you shared with your friends, but you didn’t do so earnestly.” The Rebbe then explained to his son the concept of a “good eye” and a “negative eye.”
The youngster was so distraught by his father’s rebuke that he broke out in tears, eventually vomiting all that he had eaten.
Hearing his cries, his mother entered the room. Upon realizing what had occurred, she told her husband: “What do you want from the child?”
The Rebbe answered: “It is good [that he is crying]. This way good character traits will be ingrained in him.”
(Sefer HaSichos 5705, Pg. 11)
