It was the custom of Rabbi Menachem Mendel of Kotzk to remain in his Sukkah even in a pouring rain. He insisted on staying in the Sukkah even when the Halacha permits eating inside the house due to inclement weather conditions.
He remarked, "The reason a person is absolved from sitting in the Sukkah in the rain is because a mitzta'er who 'suffers' is not obligated to be in a sukkah.
"Truth be told," said the Kotzker with a sigh, "one who feels uncomfortable with the Sukkah is exempt because he’s out of it. He is missing out on the Sukkah's special spiritual ambience, rain or shine."