It happened that the Rebbe and Reb Noson were once invited to the sukkah of a simple Jew. When Reb Noson questioned the validity of the sukkah, Rebbe Nachman remarked, “A Jew works very hard to build his sukkah, and you seek to invalidate it based on stringencies found in the Codes?!” (Aveneha Barzel, p. 25 #17).
When Rebbe Nachman was young, he himself sought to fulfill the strictest opinions found in the Codes. On one occasion, he even considered moving to another city, where the water supply could be better guarded during the holiday. Such was the seriousness with which the Rebbe took the prohibition against Chametz on Pesach (see Orach Chaim 467:13). However, as he grew older, he came to realize that stringencies in keeping the Codes was actually superfluous. The Rebbe said, “If only we were able to perform the mitzvot with simple sincerity. ‘The Torah was not given to ministering angels’ (Berakhot 25b). A person should choose one mitzvah and observe it strictly, with all its fine points; all the other mitzvot should be kept without any stringencies whatsoever” (Rabbi Nachman’s Wisdom #235).
Reb Noson once remarked, “Sometimes, because a person tries excessively hard to perform a mitzvah in the very best way possible, he ends up not performing the mitzvah at all” (Siach Sarfei Kodesh 1-571).