That's not actually clear! Homo Sapiens adaptation rate increased 100-fold once we started this civilization thing. And for most of that time our social evolution was very slow. I guess today it might have turned around, but that's a blink in the history of our race.
Oh anything really. Ranting on HN. Telling off sales clerks. Pushing to the head of the subway line. Anything you get away with because its anonymous. In the old days, you'd know every clerk, everybody in a line, and get harassed if you were antisocial.
That's very much a modern view. And not shared around the world at all. Racism is of course wrong. But social norms are the glue that holds us all together, to a degree. Its not black-and-white.
The modern tendency toward outbursts of antisocial behavior might be a product of anonymity.