A letter from the Frierdiger Rebbe to a Mashpia in Toras Emes Yeshivah in Chevron. I realize the words here may seem harsh and even degrading, but I think if taken into perspective they can be seen in a positive light, even by those who may at first be offended. The letter was written about the Talmidim of the first Chassidic Yeshiva in the Holy Land, which was very much in the hands of the "Perushim" until then. The Rebbe felt that they're not carrying out the will of his holy father the Rashab, the founder of Tomchei Tmimim, who was still alive and well at the time. He felt that they somehow seemed to blend in "too well" with the rest of the Yeshivos, and that it wasn't "Nikker" on them that they were Chabad Chassidim and Bochurim.
The fact that the Rebbe allowed for this letter to be printed in its entirety, when we know that other letters were omitted from the books of letters, tells us that this is important for us, the later generations, to know.