Well, once slavery wasn't thought of as an immoral concept, now we rightfully consider it abhorrent. Women were once considered the property of men, now we're more equal, at least in theory. To kill in the name of religion has been considered the right thing to do in several eras in history. Even today, many radical groups believe in it, but the majority of people consider it reprehensible.
Weirdly though, I experienced less racism when I met Shakespeare than when I was around in 1913. Shows how time does change and evolve, backwards and forwards.