Absolutely speaking, Do unto others as you would that they should do unto you is by no means a golden rule, but the best of current silver. An honest man would have but little occasion for it. It is golden not to have any rule at all in such a case. – Henry David Thoreau

Young men know the rules, but old men know the exceptions. – Oliver Wendell Holmes

Any fool can make a rule, and every fool will mind it. – Henry David Thoreau

There is no more important rule of conduct in the world than this: attach yourself as much as you can to people who are abler than you and yet not so very different that you cannot understand them. – G. C. (Georg Christoph) Lichtenberg