Confidence comes from preparation and knowing your stuff.
不要害怕放弃好的，去追求伟大的。
As Will Rogers would have said, "There is no such thing as a free variable."
And if you take Warren Buffett and watched him with a time clock, I would say half of all the time he spends is sitting on his ass and reading. And a big chunk of the rest of the time is spent talking one on one either on the telephone or personally with highly gifted people whom he trusts and who trust him. In other words, it looks quite academic, all this worldly success.