“Do not do to others what you do not want them to do to you" 
If you want an example of maxim certain to be wise, this is it: life-saving, sensible, fair, virtuous but also condition of a happier, peaceful life;
because what goes around comes around and, time given, as you saw so shall you reap.
This, the Golden Rule, is the core of axial wisdom, in which all religions agree with obvious common sense, from Confucius to Christ to Kant, in many tongues and formulations. As the famous rabbi Hillel observed, the rest of the sacred writ  is commentary. If urged to sum it up, on one leg, in positive terms, today, I would say cautiously: “Respect other people as you need to be respected.”
The Golden Rule is a matchless, elegant piece of wisdom. Confucians, Hindus, Old Egyptians, Zoroastrians, Buddhists, Jews, Christians, Moslems, all granted that this is a good thing, easy to understand and fair to do.
Stick to this axiom in good faith and you will be of the civilised, with a chance to keep out of harm’s way. You are well advised to love your neighbour as you love yourself , because most probably, sooner or later, you will need him as he will need you. If we all did this, our life would be that much less harsh, kinder and happier; if you respect the Golden Rule you are entitled to live as you let live.
The advent of the civilised human person starts with this unnatural bet on the reciprocity of good will, thrown in the face of Nature’s survival of the strongest. (In fact, even animals seek peace and try their hoof at cooperation.) Without this first step of a social contract, humans are condemned to mutual fear and hostility; an endless prisoner’s dilemma. That leads inevitably to the solitary, poor, nasty, brutish, and short life of Man wolf to man - engaged in the war of all against all described by Thomas Hobbes 
With or without the fear of God, to nourish the trust that people will have for us the regard we have for them, speaks to our reason and to our common sense.
So far so good. Nevertheless, the Golden Rule is not as neat to apply as it to understand.
The Golden Rule is a compass not a measuring staff. Based on it you have a North Star to orient your course. It is a guide not a chain. You will know by it the wise direction. You must still decide with your own head and common sense what you do and how far you go.
The breach of the golden rule is not that you stray from it when you must; but rather that you do not follow it when you can.
It appears that attention is fleeting while we encounter other people; mysteriously, we forget that they may be like us beyond our differences; we fail to consider their point of view and we neglect to imagine what it would do to us if we were treated in the same way. And of course they do not seem to care much for us.
Practiced rigidly, as a Kantesque imperative, any variant of the golden rule is horse's blinkers, leading to unilateral weakness, utopia or to outright double-faced hypocrisy.
To keep the score of reciprocity people have four guardians of lesser nobleness who would take an eye for an eye: memory, reputation, gratitude and revenge. And laws. We do not spit in the well for fear that we may have to draw water from it again.
To prevail by its’ obvious benefit, the Golden Rule needs time, a perspective of living together, of meeting again...
In short encounters, various hit-and-run scoundrels and idiots - when they see the golden compass at our wrist - profit of it to abuse us. Worse yet, the corrupt, do it to us “before we do it to them”  just because they lost hope in good-will and reciprocity or never had it. For those, be good but carry a stick.
Difficult questions arise when other people do not care to respect the rule. Would you keep golden anyway, leap for faith for goodness’s sake, turn your other cheek, resign with stoicism and masochism, or will you do something against the transgressor, to stop evil and to help the good rule prevail? Let me believe in my weakness that there is a justified common sense limit to one-way goodness, as non-violence should tolerate everything except its negation, violence.
How to count with people who detest the things that are good for you and who value things you hate? People do have different needs, like the stork from Aesop`s fable who could not eat from a shallow plate while the fox could not eat from a high jar. As people are not equal, reciprocity must be, generously, unequal. The Golden Rule is understood and works only when translated in local language and personal meaning. Otherwise it sounds like an arrogant: “Come and live in my world, by my rule!”
What to do however with the spineless thinkers who concede that everything is relative, cultural and national, that everything goes? Trust your judgment, I would say and be in good faith “you only understand the golden rule by living it » [5a].
And what about those paragons who come to force-feed you virtues and fair treatments which you do not want and in exchange blackmail you to reciprocate? Knock on them, they will sound empty.
Be certain then that you and the other live in the same moral sphere; by which I understand sharing the main values and obligations of being human, not beast and prey. If the moral spheres are radically incompatible, the golden rule must be enforced by negotiation - from a distance. Those have a right to your Golden Rule who obey it. Still, you may share with them some lesser rule of mutual benefit.
With irreducibly different values, the golden rule of reciprocity is that of mutual respect. This is unfortunately a kind of apartheid: you must let the other live by his rule as you request him to let you live by yours. Live and let live! This arguable solution may work, provided the respectful distance is mutually preserved. Sad consequences for human rights! Here open the gates of Hell...
Today’s world unfortunately abolished the distances needed for irreconcilable difference to live in peace. It appears that there is a cultural limit to instant globalisation, one not measured, and which money cannot buy. Maybe there is more than one History, parallel histories, each needing their time given to time. Maybe before gold, people need bread to their fill.
Consider also some corollaries of the golden rule that should not depend on a difference of tastes and beliefs.
Spend some time and care to find out what other people want and detest; so that you are not blinded by your point of view.
Beg others, for a start, not to do to you at least what they would not have done unto them within their own values; that much should be easy to understand for everyone.
Negotiate with them not to do to you that which you would not do to them.
Request those things which, amazingly for them, you do not want to be done to you to be considered too, by your right to be different. Those who ignore your difference should expect you to ignore theirs (but this is the way of war).
It may be needed, as I mentioned, to establish private territory and borders when building one World fails. Unfortunately we must also consider force: si vis pacem para bellum. 
Do not let others do to you what you rightly do not suffer under the false excuse that they have different beliefs, better ones. Your own absolute beliefs, good, right, beyond discussion, are not justified to be imposed on differing people in their own house. If you accept other people’s right to be wrong they must too.
Without a right to be wrong there is no golden rule.
There may be some wisdom even in the tit-for-tat way we punish those who break the Golden Rule:
First of all, react proportionally, not by all-out war. Try justice first. It that is impossible, revisit History.
Those who do to you knowingly that which you would not do to them should expect to be visited an eye for an eye, not a life for an insult; an eye for an eye is the contrary of the cruel revenge some believe it to be. From Hammurabi on , it was great progress, calling for proportional compensation instead of killing each other in revenge as it was the habit of old times.
My choice looking at this mountain of real-life inconsistency is modest; to reserve my uncompromising, free-will obligation of the Golden rule to people who share reasonably my foundational values or who do not share them at all but respect them. For the rest, I do my best to navigate on track, on stormy seas.
This is my golden rule: respect all people in their difference as you request them to respect you; agree to differ!
I know that history has successive ups and downs; I believe that all civilisations decay and fall; that barbarianism will be born ceaselessly, with each newborn, with each new generation, whereas it takes long years to grow civilised.
I will still fight nature and barbarianism whenever I can and apply the golden rule, whenever I can, whatever I start, for the sake of my own dignity and well-being and for beauty in my life; and my life includes the world around me. I found it true that to have friends you better be a friend; be sincere and you will encourage honesty; be polite and you build a greenhouse of politeness; respect to be respectable, smile to be smiled to and of course, give to receive.
Do not adapt to reality. Live and let live!
 Confucius, Analects 15:23
 of the Tanach, the Old Testament
 “You shall love your neighbour like yourself.” (Leviticus 19:18)
 “...a time of Warre, where every man is Enemy to every man; the same is consequent to the time, wherein men live without other security, than what their own strength, and their own invention shall furnish them withall. In such condition, there is no place for Industry; because the fruit thereof is uncertain : and consequently no Culture of the Earth ; no Navigation, nor use of the commodities that may be imported by Sea ; no commodious Building ; no Instruments of moving, and removing such things as require much force ; no Knowledge of the face of the Earth; no account of Time; no Arts; no Letters; no Society ; and which is worst of all, continuall feare, and danger of violent death; And the life of man, solitary, poore, nasty, brutish, and short.” Thomas Hobbes, Leviathan, Reprinted from the edition of 1651, Clarendon Press, Oxford, 1929, Part I. Chap. 13. p 99.
 “You'd better do it to them before they do it to you!” Donna Hightower, This world is a mess, MetroLyrics.com
[5a] Wattles, Jeffrey, THE GOLDEN RULE, Oxford University Press, New York, 1996, vi
 “qui desiderat pacem, praeparet bellum” FLAVI VEGETI RENATI, EPITOMA REI MILITARIS, recensuit CAROLVS LANG, Lipsiae : in aedibus B.G. Teubneri, 1841 p. 65
 The code of Hammurabi writes, precursor to the Law of the Talion: "196. If a man destroy the eye of a man (gentleman), they shall destroy his eye." THE CODE OF HAMMURABI, P. Handcock (ed), The MACMILLAN Company, New York,
1920, p 33