The people I've known whom I see as good people tend to credit their goodness to following the Golden Rule. Since they know more about being a good person than I do, I will not challenge that the Golden Rule works for them. I do not however necessarily see it working for everyone.
My concern is simply rational. People differ from one another, and they will all want to be treated in different ways. If I treat the next person the way that I myself want to be treated, I may not be treating them the way that they want to be treated. I run the risk of projecting myself upon the next person while dishonoring who the next person actually is himself.
There are some things that people may want to be treated that aren't good at all. If I was suicidal and wanted the next person to kill me, I would not be justified in killing the next person. If I was a sexual masochist and wanted to be chained and whipped, I would not be justified in doing that to the next person either. Even avoiding these extreme situations, there are all sorts of differences in how people may want to be treated; and treating the next person the way that you yourself want to be treated may not be congruent with the treatment that they themselves want to receive.
The Golden Rule works to the extent that people are all similar to one another. It does not work to the extent that people are different from one another. Different people will want to be treated differently; and while the Golden Rule works – sometimes extremely well – on matters in which people are similar to one another, it does not work as well on matters in which people differ.
I have been seen as an alien all my life, and I am skeptical of the idea that treating the next person the way that I myself want to be treated would be a workable proposition. I think that much better than that would be for me to figure out how the next person would want to be treated and act accordingly. That requires brainwork; but I think that the results would be worth it. That way one can make a meaningful difference in people's lives while sowing – and benefiting from – good will.