I've been around similar buzzkills in person (been one, perhaps?), and I wonder what precisely is going on. What is the mechanism behind smarty-pants-Dave's su

I've been around similar buzzkills in person (been one, perhaps?), and I wonder what precisely is going on. What is the mechanism behind smarty-pants-Dave's suppression of others' enthusiasm? Was it that he was raising issues that weren't relevant to others' learning? Or did something in his mannerism suggest contempt for those who knew less Python than him? Or, did people become suddenly skeptical of the authority or competence of the instructor Dave questioned? I second the observation that in the right environment, attention and interest would increase, as people look for ways to give annoying-Dave his comeuppance.