You look around the world at geniuses, and they don't appear randomly, they appear in genius clusters. Athens in 50 BC, Florence 1500, Silicon Valley today. This is not a coincidence.

So the greatest source of happiness is other people- and what does money do? It isolates us from other people. It enables us to build walls, literal and figurative, around ourselves. We move from a teeming college dorm to an apartment to a house, and if we're really wealthy, to an estate. We think we're moving up, but really we're walling off ourselves.

Psychologists call it "defocused attention," where you broaden your horizons, let your mind float and drift a bit. Coffee keeps us sharp and alert. It's great if you're driving at 3 o'clock in the morning. It's not so great if you're trying to come up with the next violin concerto.

We can't love a place or a person if we always have one foot out the door.

We are shaped not only by our current geography but by our ancestral one as well. Americans, for instance, retain a frontier spirit even though the only frontier that remains is that vast open space between the SUV and strip mall. We are our past.

I'm interested in genius the way a hungry man is interested in Philadelphia cheesesteaks. I want something. I want a piece of it.

Someone like Mozart moves from Salzburg to Vienna, where all of the sudden he finds this musical city that is not only asking for music, it's demanding music of him.