Here's a short story I read:

There is a story about a university professor

who came to a Zen master to ask him about

Zen. Nan-in, the Zen master, served him tea.

He poured his visitor's cup full, and then kept

pouring. The professor watched the overflow

until he could no longer restrain himself. "It

is over-full. No more will go in!" "Like this

cup," Nan-in said, "You are full of your own

opinions and speculations. How can I teach

you Zen unless you first empty your cup?"

Out of Solitude (Three Meditations on the Christian Life)
by Henri J.M. Nouwen