Doing unto others as you would have them do unto you, isn't really optional. It's not something you can choose not to do, and it isn't something to aspire to. But that's how it's often viewed.
There is a metaphysical truth that, at the very least, other people ARE you, so how you are treating them you are treating yourself directly. But I think this leaves open room for error because there are some other parts to this that you may not realize.
First of all, you can only share love. Love IS sharing. It means joining and communing and being equal and being ONE. This is the underlying truth on which this idea is based. You CAN only share love. So this really means, you CAN only "do love" to others, you cannot actually really do anything else to others.
So when it comes to "how should I treat other people", the ONLY option that you can REALLY pursue is to love them. Love will be extended and shared to and with them. If your attitude is NOT love, IT WILL NOT BE SHARED.
So that means you CANNOT do unto others anything other than love.
There is also more to this.
Your mind, when you are believing that YOU are sinful, will become a split mind. It's a mind that believes separation has really happened. And this separation has happened INSIDE YOURSELF. Your own mind has become split. Part of this split will entail that a portion of mind remain in your awareness - conscious awareness - and a portion will be sectioned off and repressed as a place to shove your unconscious guilt. But the splitting off of that second part of mind (which produces a shadow, at war with your conscious persona), is now experienced as "not myself"
And so then you are in a state of disassociation from your whole self. The part of YOU that you think is not you, which you are trying to get rid of like crazy, you will believe you are separate from it - that it's not you. And so when some person comes along you will see them as "not you" also, and will then see IN them your own "not you" part of your own mind. You will relate to your own "not you" mind as though it belongs them them, since it doesn't belong to you. And you will attack that part.
So now you think you are "doing ego" to someone else. That you are treating them with less than love. And that means it now seems optional as to how you treat others. But really you are not even doing anything to them at all. If they were awake they'd know this. You are just attacking your own self indirectly. So you're not ACTUALLY doing anything to others, if it's coming from your ego. You literally ARE only attacking yourself.
So now we have this situation.... either you love both yourself and others, or you go into a private world where you are attacking yourself, but believing everyone else is involved. Nobody else is involved AT ALL.
Thus it's not really a case of having to then figure out how to "do unto others" in a better way. You're NOT doing unto others. The only thing you CAN share with them is LOVE. If you are not in love with yourself, you will do nothing "to" them at all, because unlove is a WITHDRAWAL from sharing.
So now we shift from trying to "do unto others as you'd have them do unto you", to something more like "do unto YOURSELF as you would have YOUR TRUE SELF do unto YOU."
Translated, that means learning to undo your own belief that YOU are sinful, which will result in you becoming aware that you LOVE yourself. You WILL then be able to extend this love to others. So learn to do unto yourself what GOD would do unto you, which is to recognize you are worthy, forgiven and innocent forever. That should be your aim, and don't be so concerned that you even CAN do anything to anyone else.
It's not because of some kind of guilt-ridden ambition to be nice to other people that you're doing this. Since you can't do unto others unless it IS love, you can forget about believing that you're mistreating people. You are only capable of mistreating yourself.
Do you REALLY believe that you can kill the Son of God? For the Father has hidden His Son safely within Himself, and kept him far away from your destructive thoughts, but YOU know neither the Father nor the Son because of them. You ATTACK the real world every day and every hour and every minute, and yet you are surprised that you cannot SEE it. If you seek love to attack it, YOU WILL NEVER FIND IT. For if love is SHARING, how can you find it except through ITSELF? Offer it and it will come to you, because it is drawn to itself. But offer attack and it will remain hidden, for it can live only in peace.
God's Son is as safe as his Father, for the Son knows his Father's protection and CANNOT fear. His Father's love holds him in perfect peace, and needing nothing, he asks for nothing. But he is far from you whose Self he is, for you chose to attack him, and he disappeared from your sight into his Father. HE did not change, but YOU did. For a split mind and all its works were not created by the Father, and could not live in the knowledge OF Him.
When you made what is NOT true visible, what is true became INVISIBLE. Yet it cannot be invisible in ITSELF, for the Holy Spirit sees it with perfect clarity. It IS invisible to you, because you are looking at SOMETHING ELSE. Yet it is no more up to you to decide what is visible and what is invisible, than it is up to you to decide what reality is. What can be seen is WHAT THE HOLY SPIRIT SEES. The definition of reality is God's, not yours. HE created it, and He knows what it is. You who knew have forgotten. And unless He had given you a way to remember, you would have condemned yourselves to oblivion.
Because of your Father's love, you can NEVER forget Him. For no one can forget what God Himself placed in his memory. You can DENY it, but you CANNOT LOSE IT. A Voice will answer every question you ask, and a vision will correct the perception of everything you see. For what you have made invisible is the only truth, and what you have not heard is the only answer. For God would reunite you with yourself, and did not abandon you in your seeming distress. You are waiting only for Him, and do not know it. But His memory shines in your minds, and cannot BE obliterated. It is no more past than future, being forever always.
You have but to ask for this memory, and you WILL remember. But the memory of God cannot shine in a mind which has MADE it invisible, and WANTS TO KEEP IT SO. For the memory of God can dawn only in a mind that wills to remember, and that has relinquished the insane desire to control reality. You who cannot even control yourselves, should hardly aspire to control the universe. But look upon what you have made of it, and rejoice that it is not so.
Son of God, be not content with nothing. What is not real cannot BE seen, and has NO value. God could not offer His Son what has no value, nor could His Son receive it. You were redeemed the instant you thought you had deserted Him. Everything you made has never been, and is invisible because the Holy Spirit does not see it. Yet what He DOES see is yours to behold, and through HIS vision YOUR perception is healed. You have made the INvisible the only truth that this world holds. Valuing nothing, you have sought it and found it. By making nothing real to you, you have SEEN it.
BUT IT IS NOT THERE. And Christ is invisible to you BECAUSE OF WHAT YOU HAVE MADE VISIBLE TO YOURSELVES. Yet it does not matter how much distance you have tried to interpose between your awareness and Truth. God's Son CAN be seen, because His Vision is shared. The Holy Spirit looks upon Him, and sees nothing else in you. What is invisible to you is perfect in His sight, and encompasses ALL of it. He has remembered YOU because He forgot not the Father.
You looked upon the unreal and found despair. But by SEEKING the unreal, what else COULD you find? The UNreal world IS a thing of despair, for it can never be. And you who share God's Being with Him, could never be content WITHOUT reality. What God did not give you has no power over you, and the attraction of love for love remains irresistible. For it is the function of love to unite all things unto itself, and to hold all things together by extending its wholeness.
The real world was given you by God, in loving exchange for the world YOU made, and which you SEE. But take it from the hand of Christ, and look upon it. ITS reality will make everything ELSE invisible, for beholding it is TOTAL perception. And as you look upon it, you will remember that it was always so. Nothingness will become invisible, for you will at last have seen truly. Redeemed perception is easily translated into knowledge, for ONLY perception is capable of error. And perception has never been. Being corrected, it gives place to knowledge, which is forever the ONLY reality. The Atonement is but the way back to what was never lost. Your Father could not cease to love His Son.