This is a pet peeve of mine. When someone says "what's the most important thing?", the answer can't be "every thing is most important". We're being asked to prioritize by someone who's looking for an entry point. Even if it's wrong (or at least not the most correct) answer, we should give him a concrete answer.

Bravo!++ Too bad I can up-vote this only once.

What you say is so true. Both the expert and the beginner can read a manual page and understand it, at least at the denotational level. The difference is that the expert has a perspective the beginner doesn't have; for the novice all the concepts come across as having roughly equal weight; the expert can pick out the Big Deals from the trivialities. The best thing the expert can do for the novice is to share this perspective, even if it is an imperfect, limited, one-sided perspective. It is far better than the nearly total lack of perspective the beginner has.

One of the greatest gifts I ever received was a hand-written list of "books that matter" that a college professor gave me a few days after I asked him for it. He could have just pointed me to the library; I'm forever grateful he didn't. Reading those books had a greater impact on the rest of my life than all of college. Your perspective (i.e. that ability to prioritize that comes from experience) is truly precious; an off-hand answer like "read everything" devalues it.