So, as of this comment, all I know is that Simon Sinek has a book called The Infinite Game. This book has an interesting premise, about which I just read a short writeup and analysis. I have also been told that Sinek has excellent presentation skills.

Strangely, in the middle of these two comments, I was told that people should not take anything from Simon Sinek. Why?

Could you expand on this? I've certainly been enamored with his presentations, although I don't think the ideas he presents are necessarily original, but he has a great knack for formulation/synthesis and distilling the ideas to their essence.

Like this article, he's not the end-all-be-all but certainly worthy of consideration as part of forming a grander perspective in life.