To give a different spin on this, the Buddhists say that our existences here are for three purposes:
to wonder,
to struggle
and to grow. .
I cannot recall who said it but everyone we meet is fighting a battle we know nothing about. Therefore, we should always be kind to all. Some time ago, I was on my way home from a long, hard night as an EMT, I pulled up beside a car that has stopped at light just as the sun was beginning to come up. The driver was on my right and as soon as the light changed, he hit the gas and hung a left turn right in front of me. I was tired and a bit slow starting off, which was fortunate, because I had to stand my car on its nose to avoid t-boning him. He had also hit his brakes, coming to a halt about a foot away. I was tired, and cranky, opened my door, got out and was fully prepared to tear him a new one. As I approached him, he rolled his window down and began to babble an apology, but with tears streaming down his face. He was obviously distraught and between sobs told me that he had just come from the hospital where his wife had just died. My anger immediately disappeared, and as I waved him off on his way home, I felt horrible and did for days.
Be kind. Always.