This jumped out at me:<p><i>“Part of the reason Sheryl was able to say to me so bluntly, ‘You sounded stupid,’ was that I knew that she cared personally about me. She had done a thousand things that showed me that.”</i><p>This suggests that before one can practice radical candor, one needs to build a foundation of caring and trust first.  Without it, my experience suggests that the results will be more hit-or-miss -- some people just get defensive almost no matter how you frame it.