Passover, the Incomplete Festival
Most Jews don't understand that the Exodus we celebrate at Passover is only a prelude to the main event at Mt. Sinai.
At Rosh Hashanah, God evaluates our performance as His partners in the covenant of Torah. At Yom Kippur we renounce our actions that amount to violations of the contract with God and resolve to improve our level of compliance. At Sukkot, we appreciate God's tender protection and abiding love despite our failures, which is the reason behind our spending the week of this most joyous of festivals camping out in huts (in Hebrew, sukkot), unprotected by the sheltering architecture of our permanent dwellings.
Sukkot is also the apocalyptic Jewish holiday, anticipating the time when the priestly purpose of Jewish existence will be fulfilled, with the world's peoples coming up to Jerusalem's rebuilt Temple "every year to worship the King, the Lord, Master of Legions, and to celebrate the festival of Sukkot" (Zechariah 14:16).
When you step back to a contemplative distance and observe the integrity of the Torah's calendar, it becomes obvious why leaving out any part or element in the whole, perfect structure-like, for example, venerating Passover but blowing off Shavuot leads to the structure's collapse.
What exactly do we do on Shavuot? We meditate on the fact that as Jews we have a mission statement, the Torah. The Torah reading, chanted in synagogues on the first morning of the festival's two days, is like a dramatic reenactment of the Sinai revelation. The day has few other mandatory observances, beyond the requirement to refrain from work much as we do on the Sabbath, so as to increase the impact of our contemplation. Many Jews prepare for Shavuot with an all-night Torah study session known as "tikkun leyl Shavuot," intended to demonstrate that unlike our ancestors who stood at Sinai, we are fully prepared to receive God's revelation.
I suspect that this joyous, awe-inspiring, and crucially important day is largely ignored in American Jewish culture because its message makes many contemporary Jews uncomfortable. More than any other festival, it calls us to accept all the ramifications of our commission by God to be Jews-specifically, adherence to the 613 commandments given at Mt. Sinai.
The joys of the eternal Sinaitic covenant ascend to heaven, but the responsibility to follow Jewish law (halakha)-a body of legislation still being clarified and applied by Jewish sages to unprecedented modern circumstances down to our own day isn't compatible with every lifestyle, to put the matter mildly.