A cup of tea

In the early 20th century, Zen master Nan-in received a university professor who came to ask about Zen. But instead he only talked on and on about his own ideas.

Nan-in asked him if he'd like some tea. The professor agreed.

Nan-in brought the pot and cups and proceeded to pour his visitor’s cup full, and then, while the man continued to speak, Nan-in kept on pouring the tea.

The professor watched the overflow until he could no longer restrain himself. “You fool! Can't you see it is overfull. No more will go in!”

Nan-in replied, “Like this cup, you are also too full of your own opinions and speculations. How can I show you Zen unless you first empty your mind?” 

There are several versions of this story. The protagonists may vary, it may be a different Zen master : Hakuin or Bodhidharma... The visitor, instead of a professor, may be  a high ranking Samurai or a Chinese Lord...

 
Some people are not interested in learning new things because they believe they know everything they need to know. Their cup is plain. 

It happens all the time in Martial Arts :  some Karate people don't think anything good can come from Judo, Wrestling, Boxing or MMA (and vice-versa).

But is is not limited to Martial Arts... Some people practice Zen, and don't want to hear about Vajrayana or Theravada Buddhism.

Generally speaking having your cup full is the mark of age. Younger people usually still have the ability - and willingness to learn...

Some brilliant elders have seen it all, and can't understand  that younger people might have the audacity and lack of common sense to question the way they teach and do things...
 
I am getting older too. And tired of wasting my time with this kind of people.  I won't be here forever and find it is a better use of my time and effort to try to share the little I know with "not so advanced people" who still have the humility and the willingness to learn. 

If you want to learn from me, empty your cup. If you are not interested, that is perfectly okay with me... 

Don't try to teach a pig how to sing - You'll waste your time, and you'll only aggravate the pig...

(Anthony de Melho)