When Rav Shneur Gorelick, the legendary Rav of Kfar Chabad, traveled to the Rebbe in 5721 (1961), he was over eighty years old. He was one of the first students at the great yeshivah in Lubavitch, and had spent much time with the Rebbe Rashab and the Previous Rebbe.
When he entered yechidut (private audience), the Rebbe stood up and offered him a seat. He refused to sit. When he saw that the Rebbe continued to stand, he said emphatically, “at my age I didn’t travel overseas to meet a gaon (genius), to meet a maskil (scholar) in Chassidus or a tzadik. I made the journey to be by a Rebbe. And before a Rebbe, I have never sat!”
The Rebbe accepted this and sat down, while Rav Gorelick continued standing. The yechidut lasted for two hours and forty minutes.