Reb Shmuel Munkis, a chassid of the Alter Rebbe, was one of those present at a
farbrengen of chassidim. He was known to all as the jokester who was always on the jolly side. It once occurred that roasted lungs (a delicacy) were brought to the
farbrengen as an appetizer to accompany the
l'chaims. Reb Shmuel was the one charged to distribute the exotic meat to those assembled.
He jumped around with the tray of meat on the palm of his hand and was extremely annoying to those whose tongues were anxious to taste it. His bizarre behavior made them want to put him on the table and give him a good-natured thrashing! But Reb Shmuel danced around with it until finally he dumped it into the trash.
A little while later, the butcher came running in frantically. "Do not eat the meat! The meat is not kosher!" Through a misunderstanding, his wife had mistaken this piece of non-kosher meat for kosher, and had given it to them by mistake. The butcher wanted to be sure that the chassidim did not partake of the meat.
This even intensified the feelings of those assembled toward Reb Shmuel. "How did you know that the meat was non-kosher? Are you practicing ruach hakodesh (Divine inspiration) in revealing things the ordinary person does not know? What gives you the right to do that?" At this point, they really wanted to get back at him for his outlandish behavior.
Reb Shmuel responded, "I have learned from my mentor, the Alter Rebbe, the following: Only something that is prohibited creates such strong pangs of desire, whereas something permissible does not get the person so excited. When the meat arrived, I had a tremendous longing for it and I also saw this lust on the faces of those assembled, so I instinctively knew from my studies with the Alter Rebbe that I must not allow myself or others to partake of this prohibited craving!"
So I was keeping my promise "not to enjoy a material pleasure!"
Sefer HaSichos 5703, p. 176