I'm an absolute nobody compared to Tesler, but I remember a hack week we did at Amazon probably in 2009 or so - the SVP (reporting directly to Jeff) was giving a little intro speech to what they hoped to see out of the hack week, and he ended with an admonition: "Whatever you do, DO. NOT. ATTEMPT. TO. REDESIGN. THE. SITE. UI.", and then later was told by him that Jeff will literally rip your head off if he caught wind of it.