It’s easier to learn by day when your work ethic is operative and you feel you must do something constructive with your time. Learning by day represents the service of obligation and responsibility. Learning at night represents the service of love. When we stay up and learn on the night of Shavuot we express our realization that Torah is not a burden but, rather, the greatest joy.
We now understand why Simchat Torah is not observed on Shavuot. The relationship has just begun and there is much work to do. Singing and dancing will come later. We rejoice on Shemini Atzeret because that is when we complete the annual Torah reading cycle. We thereby affirm that one who is faithful and constant in his studies will uncover the beauty of Torah.
Our relationship to Torah is framed by profound commitment to the hard work of studying and performing the commandments as well as a realization that the ultimate goal of our service to Hashem is a feeling of sublime joy. May we merit attaining it.
Chag Shavuot Sameach.