+1
The most Freiliche Yom Tov meals I've experienced were in drenching rain.
+1,000
But shouldn't that depend on the individual and not be a blanket minhag?
It's a state of mind that we strive to reach. And most guys who go through the Chabad system do reach it. Obviously one can do what they want, but after learning the chasidus/kabala behind the importance and meaning of the sukkah the notion of rain hindering it is laughable. Similar to the beard-some guys may be on the fringes, but often the beard is that last thing to go as it's importance al pi chassdus is stressed so much. But if someone doesn't feel it they're free to do what they want.
My 10th grade rebbie told a story from when he was on bochur shlichus. He bumped into a woman who was walking in the pouring rain with no umbrella. When they offered her theirs she asked if they were chabad chassidim. When they answered affirmatively she told them that she used to work in the house of the Rebbe.
One day it was pouring and she didn't make it to the store to buy milk for the Rebbe's mother. The Rebbe then insisted on going out himself to buy the milk and the least she could do was offer him an umbrella.
"Why would I want to separate myself from Gds blessings" was the Rebbe's response. Since then she had never used an umbrella.
Vd"l.