If I could live my life completely by one maxim, this would be it. It seems to fit so perfectly with my perception of how people should be treating each other.
This advice was taught by Jesus during The Sermon on the Mount. It can be found at Matthew chapter 7, verse 12.
Before you flame someone, ask yourself "Would I want them to flame me?" Before driving dangerously or drunk, ask "If I were driving, would I want a dangerous driver near me?"
Unfortunately, such a maxim is connected to a religion. Hence people will shun the advice simply because it is religious, or it is not "from their religion."
I learnt this from the Bible, but I don't view it as a Christian Value. As I see it, treating others as you would want to be treated by them is a fundamental part of being a moral, caring and thoughtful human being. I'd guess that most of us know someone who we hold up as a great person to know, someone who is always nice to others and is great to be around. It doesn't always follow that this person will be religious, they just care about their fellow humans - They are selfless at their core. I strive within myself to be such a person; a calm, Buddha-like, serene, happy, thankful, helpful guy.
So, the advice for Noders? Before downvoting or making a silly softlink, ask yourself "Would I want anyone to do this to me?" (dizzy grins, ducks and runs)
I suggest you read Dr. Plaid's writeup below; it explains the difference between a couple of different interpretations of this rule. Several people have misunderstood this phrase, or taken it too literally.