Curiosity might be pictured as being made up of chains of small questions extending outwards, sometimes over huge distances, from a central hub composed of a few blunt, large questions.
He that writes to himself writes to an eternal public. That statement only is fit to be made public, which you have come at in attempting to satisfy your own curiosity.
A friend, therefore, is a sort of paradox in nature. I who alone am, I who see nothing in nature whose existence I can affirm with equal evidence to my own, behold now the semblance of my being, in all its height, variety, and curiosity, reiterated in a foreign form; so that a friend may well be reckoned the masterpiece of nature.