Robert A. Heinlein said this quote
“ He never once repeated himself and he never used either profanity or obscenity. (I learned later that he saved those for very special occasions, which this wasn’t.) But he described our shortcomings, physical, mental, moral, and genetic, in great and insulting detail.But somehow I was not insulted; I became greatly interested in studying his command of language. I wished that we had had him on our debate team. ”