Everyone has their idiosyncrasies. One of mine is a particular fascination with the number six.
It might have something to do with the fact that I was born on the 6th, as was my father (today would have been his 87th birthday) and one of my sisters; my mother was born on the 30th and another of my sisters was born on the 12th (the only exception among the six members of my immediate family is my remaining sister, who was born on the 26th instead of a multiple of six).
Perhaps as a result, I've always considered 6 to be a lucky number. When I played Little League baseball as a kid, I always wanted to have a uniform with number six on the back. My favorite baseball player in my childhood was left fielder Roy White of the New York Yankees, who wore number six. My favorite work of music is Bach's Cello Suites: six suites each comprised of six movements. I'm in the midst of writing six books about my favorite thinkers. My book on Rand has 6x8 (48) chapters, on Nietzsche 6x12 (72) poems, on Thoreau 3x6 (18) chapters, on Epicurus 4x6 (24) chapters; my forthcoming book on Aristotle will have 6 chapters. After the Aristotle book (and one on Pyrrho, slated to have 12 chapters), I plan to write a book entitled "Being Human" that will have 6x6 (36) chapters and incorporate a six-step process of practical deliberation, a six-fold division of life pursuits, and six perspectives on life (re-using the six directions of ancient Greek thought: up and down, forward and backward, left and right). And so on. I suppose it's not entirely rational, but it's one way for me to order my thoughts and activities...