Given the small percentage of human population on the fringes as to how they specifically would like to be treated (bullies with low self-esteem, sadomasochistic folks, people who just love a good fight), I would say that Matthew 7:12 would be a socially acceptable and morally valid principle in the vast majority cases compared with the average. As to being able to tell exactly which personality type you are dealing with at any given moment, I suppose that it would be kind of similar to quantum mechanics in that you cannot ascertain exactly where an electron is located at any specific time due to the “Heisenberg uncertainty principle” BUT, however, you can determine the orbital area (the “electron cloud”) wherein an electron is likely be present about 90 percent of the time.
So in other words, deciding to start from the precept that “most people respond to kindness” and going from there would, in fact, be your best bet, or at least probably a good 90 percent of the time.