There are three places in the writings of Rav Nahman that emphasize not to be extra strict. I realize this looking for extra things to be strict about is a fundamental flaw in my own personality. One is supposed to keep Torah plain and simple --not to add and not to subtract. However I would like to suggest that this is not to say there is nothing one ought to be strict about. Rather it is a matter of getting the priorities straight. Things that the Torah itself is strict, (like not to do idolatry), one ought to be extra strict. Good character also is high on the list of the things the Torah is strict about. As gaining good character trait is one of the reasons for the mitzvot as all the Rishonim that list the mitzvot go into [for example Sefer HaChinuch].
