A lot of these moral precipts are full of fallacy. For example, look at how well an-for-an-eye worked for the middle east.
The Golden Rule is no exception. "do unto others as you would have them do unto you" - you DON'T see any problem with that? If not, think harder...
The problem with this so-called rule, which most blindly follow, it is steeped ins subjectivity - the way I lead my life, and want to be treated, may not only fail to coincide with the way you live your life, but also may be an infringement upon your own beliefs. Opening the door for a lesser able-bodied person may be seen as insulting, whereas having a door opened for you, who is presumably able-bodied, may be seen as a kind gesture. Careful in projecting how you want to be treated onto others, you may find yourself in hot water as the guy above did.