Did you ever introduce someone to something you were good at only to have them beat you at it later? Take for instance World of Warcraft, you show someone how to play WOW when you are level 60, and the next thing you know they are playing 40 hours a week, and have 3 level 80s before you even get one! I think Asian cultures have this fear more then western ones. That’s mainly why a lot of knowledge was lost, because the masters never show the apprentice everything, for fear of losing their own self worth. It’s a shame because the master eventually dies, and the art slowly loses pieces until it’s gone. I think this is because Asian cultures handle relationships using respect, rather then love. If they apprentice loves you they are likely to take care of you even after you reveal everything. However if the relationship is based on respect, and you have held yourself higher based on your knowledge, then you run into the risk of the apprentice losing respect for you once you have revealed all your knowledge. I think some families are formed this way too. They are built on respect, rather then love or both.