I'm rereading the Hitchhiker's Guide to the Galaxy in one volume. It is 815 pages long.
There is a point, where Arthur has defeated Agrajag and learns how to fly at which his character changes. He is no longer afraid of the Universe and becomes more confident. (e.g. Standing up to Thor at the party and winning Trillian back, knocking the Krikkit Robot's head off etc.)
That episode is on page 407-408, the exact midpoint of the book.
Earlier, the chapter explains the Holy Lunching Friars of Voondoon who
...claimed that just as lunch was at the centre of a man's temporal day, and man's temporal day could be seen as an analogy for his spiritual life, so Lunch should be seen as the centre of a man's spiritual life..."
Page 407-408 is sort of the "lunchtime" of the book, where Arthur has his spiritual epiphany. Was this intentional?