The Washington Post: What will future generations condemn us for?

'''Still, a look at the past suggests three signs that a particular practice is destined for future condemnation.

First, people have already heard the arguments against the practice. The case against slavery didn't emerge in a blinding moment of moral clarity, for instance; it had been around for centuries.

Second, defenders of the custom tend not to offer moral counterarguments but instead invoke tradition, human nature or necessity. (As in, "We've always had slaves, and how could we grow cotton without them?")'''

A couple of guesses from myself: the staggering amount of meat we consume, and the prohibition of cannabis.

Linkage from @duncan.