My soul thirsts for You; my flesh pines for You (Psalms 63:2).
One Yom Kippur, after the Maariv (evening) services that ended the 25-hour fast, Rabbi Levi Yitzchok of Berdichev exclaimed, "I am thirsty! I am thirsty!" Quickly someone brought him water, but the Rabbi said, "No! I am thirsty!" Hastily they boiled water and brought him coffee, but again he said, "No! No! I am thirsty!" His attendant then asked, "Just what is it you desire?"
"A tractate Succah (the volume of the Talmud dealing with the laws of the festival of Succos)." They brought the desired volume, and the Rabbi began to study the Talmud with great enthusiasm, ignoring the food and drink that were placed before him.
Only after several hours of intense study did the Rabbi breathe a sigh of relief and break his fast. The approaching festival of Succos with its many commandments - only five days after Yom Kippur - had aroused so intense a craving that it obscured the hunger and thirst of the fast.
It is also related that at the end of Succos and Pesach, festivals during which one does not put on tefillin, Rabbi Levi Yitzchok sat at the window, waiting for the first glimmer of dawn which would allow him to fulfill the mitzvah of tefillin after a respite of eight or nine days.