An expert is...
A good teacher or an expert is someone who, after listening to you for five seconds, knows : what you know , what you don't know , what you want to know , and what you need to know in order to achieve what you want to know . Otherwise both of you will be spending unproductive hours going around each other repeatedly. I am sure you have see this only too often, where two parties confuse each other on different frequencies. Hence, if you are offering advice, do take a step back and spend five seconds to figure out what the other person knows, does not know, and wants to know, so as to offer what he needs to know.