I think the most ridiculous phrase in existence is 'Those who can't
do, teach'...nothing could be further from the truth. One must have
extensive knowledge in one's subject or craft in order to even begin
trying to teach it. Not to mention the enormous amount of patience
required to teach and inspire students who - for the most part - don't
even want to be there. Teachers are remarkable - I have so much respect
for what they do.