"Just as one must recognize shortcomings, so, too, one must recognize his own
(good) qualities" (Sefer HaSichos 5710
, p. 386).
To understand this statement - related many a time by our chassidic masters - it is important to note that the emphasis of "his own" is used only when addressing the (good) qualities. When mentioning the shortcomings, however, only the word "shortcomings" is stated.
The reason is that, in essence, sins and shortcomings are foreign to and don't belong to a Jew. The only reason a Jew comes in contact with sin is that he has been charged with a mission to elevate this world; thus inevitably he comes in contact with and is influenced by the negative inclination within him. However, even after he succumbs to sin, it is truly not his, but merely an extraneous matter that lingers on due to outside influences and environment.
A Jew must be aware of his quintessential essence - his goodness and kindness - for this is his true self.
Toras Menachem 5742, vol. 1, p. 53