“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, on which all religions and philosophers agree, from Confucius to Christ, in many tongues and formulations. As the famous rabbi Hillel observed, the rest of the sacred writ  is commentary.
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 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.
Without this first step of a social contract, humans are condemned to mutual fear and hostility. 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 
So far so good. Nevertheless, the Golden Rule is not as neat to apply as it to understand.
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.
The Golden Rule is a compass not a measuring staff. 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 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.
To keep the score of reciprocity people have, providentially, four guardians: memory, reputation, gratitude and revenge. And laws. We do not spit in the well because we may have to draw water from it again. To apply, the Golden Rule needs however time, long-time relationships.
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 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? Let me believe in my weakness that there is a jusified 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 wisely unequal.
What do you do with the wobbly moralists who concede that everything is relative, cultural and national, that everything goes and must be accepted?
And what about those who force-feed you virtues and fair treatments which you do not want and in exchange blackmail you to reciprocate?
Be certain then that you and the other live in the same moral sphere; by which I understand sharing the main values and obligations. If the moral spheres are radically incompatible, the golden rule must be preceded by negotiation - from a distance. Those have a right to your Golden Rule who obey it.
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 peace. It appears that there is a limit to globalisation.
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 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 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 tit-for-tat wisdom even in the way we punish those who break the Golden Rule:
First of all, react proportionally, not by all-out war.
Those who do to you knowingly what 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; that all civilisations decay and fall; that barbarianism is born ceaselessly, with each newborn, with each new generation, while 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 well-being and for beauty in my life. 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
 “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