A very basic one would be the realization that everyone else is more unlike you than like you.
Once this idea sinks in, it generally promotes empathy because you stop judging others by the "golden rule" (do unto others as you would have them do unto you), and start thinking about the (perfectly sane and logical) mindset and circumstance that could lead to a particular action or idea. Once you go deep enough you start to recognize the patterns within patterns.
It allows you to take others as they are, rather than as an imperfect you.
Once this idea sinks in, it generally promotes empathy because you stop judging others by the "golden rule" (do unto others as you would have them do unto you), and start thinking about the (perfectly sane and logical) mindset and circumstance that could lead to a particular action or idea. Once you go deep enough you start to recognize the patterns within patterns.
It allows you to take others as they are, rather than as an imperfect you.