It's so easy to judge people by the way they act, look, react. But do you know who they are? What their background was like? How their day is going. What is going on in their life, at that moment or point in time.
We can't look at a person and say we know who they are.
Matthew7:1,2 " Do not judge others, and you will not be judged. For you will be treated as you treat others. The standard you use in judging is the standard by which you will be judged."
Luke 6:37 starts the same. "Do not judge others...."
James 5:9 "Don't grumble about each other, brothers and sisters, or you will be judged. For look--the judge is standing at the door."