It could be rather bad. Especially if it hit your house:
https://www.newscientist.com/article/2128512-ancient-carvings-show-comet-hit-earth-and-triggered-mini-ice-age/
But what if it hit Kim Jong Un’s house? Or Abu Bakr al-Baghdadi’s? Or Ayman al-Zawahiri’s cave? Or the Kardashians?