When I worked in the sugar industry I remember once discussing a problem with a young and junior colleague. I was absolutely certain that I had the right answer but he argued and put another view. I found myself getting irritated and probably I showed it. It would have been easy for him to shrug his shoulders, abandon the argument, and with yes-sir, yes-sir on his lips opt for the easy life. But he did not, and he turned out to be right, and thus saved me from embarrassment and, more importantly, the business from error and some expense.
Any man in command surrounds himself with yes-men at his peril. Those that mollify and soothingly applaud may be nice to have around but the shrewd top men know very well that a thorn in the side, sharp and even painful, does their cause much more good than any number of soft-cored apples of their eye.