The Rebbe had a custom on the first night of Pesach of visiting the sedorim of the various mosdos; the Yeshiva kitchen at 1414 President St., FREE, Machon Chana and at times Hadar Hatorah. The Rebbe would come in to see how everyone was ready for the seder with their Kaara (Seder plate). This custom went for many years.
In 5737 (1977) when visiting Machon Chana, the Rebbe asked who would be conducting the seder for the girls. The Rebbe was told that it would be Rabbi Moshe Feller (head shliach of the upper Midwest in MN). The Rebbe then asked who would be asking the four kashes. When the Rebbe was told that it would be (the then young boy) Mendel Feller (today Rabbi Feller, Shliach in MN), the Rebbe turned to the child and pointing to his father Rabbi Moshe Feller, asked “Does he know the answers”? Everyone in the room laughed, perceiving the Rebbe’s comment as a humorous one. The Rebbe gave his blessing and left.