Every day brings a ship, Every ship brings a word; Well for those who have no fear, Looking seaward well assured That the word the vessel brings Is the word they wish to hear.
You have, let us say, a promising politician, a rising artist that you wish to destroy. Dagger or bomb are archaic, clumsy and unreliable - but teach him, inoculate him with chess.
In a discussion of this kind our interest should be centered not on the weight of the authority but on the weight of the argument. Indeed the authority of those who set out to teach is often an impediment to those who wish to learn. They cease to use their own judgment and regard as gospel whatever is put forward by their chosen teacher.
My weaknesses... I wish I could come up with something. I'd probably have the same pause if you asked me what my strengths are. Maybe they're the same thing.