Some people can take your breath away with their kind words. Others can knock the breath right out of you with their cruel words. Why?

I guess the middle rarely gets much attention. It is the extremes we notice and focus on. Why are the extremes so EXTREME? Unfailing kindness at one end and Demonic Cruelty at the other end?  The extremes to which human  beings can go is often unbelievable. Do you ever wonder why that is?  Why extremes are what we thrive on and the middle is often ignored?