Steve Jobs did this really well. If you want to show authenticity, you need to show both your good and the bad side. All we see from Zuck is his good side and that's why he comes across as pretentious.
That's an interesting insight that I never really realized before. I think a lot of people try to pinpoint why Steve Jobs is and was so respected despite the negative ways he treated people. I may have lost respect for him through these accounts, but I don't think I've ever questioned his authenticity.