Sam from Chicago wrote:
This is my first time experiencing Shavuot in a yeshiva environment. I'm told that everybody stays up all night studying Torah, which sounds fun but at the same time I'm a little wary of doing so. In school I once had a paper due the next day which I stayed up the entire night writing; in the morning my brain felt like fried tofu and I could hardly function. How important is it to stay up all night on Shavuot and why; or perhaps it's more important to get a good night's sleep?
Many, especially in the Yeshiva world, have the custom to stay awake and study Torah the entire night of Shavuot.
Shavuot celebrates the day when G-d gave us the Torah on Mount Sinai. By studying all night, we show our love and enthusiasm for this precious gift.
Another explanation is that the Jews at Mount Sinai slept late on that historic Shavuot morning! G-d had to "wake them up" to teach them the Torah (sound familiar?). We rectify this by staying up all night, to ensure that we won't sleep late on this day.
Staying up all night is not a halacha or a Jewish law, but rather a custom for those who feel they are physically up to it. If you won't function properly the next day, you should not stay up the whole night.