Having shadowed many physicians and gotten to just hang out with residents/attendings, any other premeds get irritated when doctors ask you things like "oh why do you want to do this? This stinks!", "I wouldn't do this again if I could, too much work for too little pay", or the classic "If i could do it all over again, I wouldn't"
I think its just bad advice to give to impressionable young adults who are clearly very interested in the profession; in a humorous setting its fine, but to have doctors openly announce they dislike their job and aren't passionate and wouldn't do this all over again is just disheartening...to me, at least.