It can be harmless, and you probably have all felt it.
To know what it is, watch this video and think about how you feel:
Are you laughing? Did you feel any joy from watching this person (hilariously) suffer? * i literally canot watch this without laughing my head off every time.
That feeling is Schadenfreude.
Now it's not necessarily evil of us to find pleasure in watching fail videos or America's Funniest Home Videos. You could very well argue its part of our nature.
The only problem is, the most obviously way that it is being felt by American society right now, might actually ruin us.
Donald Trump's campaign was ridiculous (depending on how you feel about him, that could be a positive or negative things) and his political stumbles made his opponents and 'haters' be fillllled with schadenfreude. The elated feeling you got from sharing some stupid tweet he wrote or some ridiculous mistake he made - there was that schadenfreude.
But the media saw that ridiculing, the laughter and shock, as interest. Trump would get them views.