There is a well-known custom in Am Yisrael to eat dairy products on Shavuot. Although it is not a mandatory law, there is something special when it comes to customs. The fact that it affects people's positive feelings for food and creates good will allows it to touch and express the deeper meanings of the holiday. Sometimes in a unique way, one's intuition can be very accurate. It is a very similar thing with customs. I'd like to list a few explanations for this custom and explain how each reason describes a deep and very accurate aspect of the holiday. Perhaps, this exceeds the effects that a mandatory mitzvah could even accomplish.
Matan Torah is a Wedding
The counting of the Sfirat Haomer is similar to the counting of the days that a wife undergoes in purifying herself for her spouse. Only for the Omer, it is for seven full weeks of seven days per week. This conceptualizes the thought that Matan Torah is a great wedding, where Am Yisrael, the bride, connects with God. This aspect mentioned in the Magen Avraham (according to the Zohar), basically describes an amazing relationship of love we experience on Shavuot with Hashem.
The Torah Elevates People
The angels that came to eat at Abraham's tent did not separate meat and dairy. One of the customs mentioned (see the Be'er Hetev) is to first eat dairy and after that meat to show the difference between us and those angels who ate with Abraham. Angels don't really eat, neither do they have a 'yetzer hora', an evil inclination. Before God gave the Torah to Moses, the angels tried to convince Him to leave the Torah in heaven with them. Moses convinced Hashem to allow the Torah to enter the 'lower world' by showing how the laws are relevant precisely to human beings- using natural ways (bavli Shabat 88). The angels, of course, have no need for the Torah. The purpose of the Torah is to upgrade and elevate people who exist in THIS world.
The Torah Has Demands
When Am Yisrael received the Torah there were suddenly many new laws that they were commanded to follow. The preparation required for eating meat is more involved as compared what it takes for dairy products. The slaughtering, salting etc., required, forced them to eat dairy on Shavuot (Mishna Brura). The Torah has many demands and we are required to have Yirat Shamayim, together with great love that we have for our mitzvot. The laws are very detailed and effect every aspect of our lives, including our kitchens. We are ready and capable for this.
The Torah is Sweet
I believe that all the explanations above are true and together introduce a deep insight into the essence of the holiday of Shavuot. The simple act of following a popular custom can reach out and touch the deepest meaning of the holiday in such an accurate way.
Rabbi Yonatan Kirsch was born in NJ but grew up in Ginot Shomron after his parents moved to Israel. He teaches at the Hesder Yeshiva in Sderot, where he lives with his wife and family, after receiving his semicha from the Chief Rabbinate of Israel. He is author of the book "Ma'alot Hamikve", published by Dabri Shir, and served as a combat soldier, is a certified tour guide.