We usually judge people by their outer appearance, their surrounding, the environment in which that persons lives , their family members etc.

But we just don't have any right to judge anyone. There is possibility that what we are assuming about someone is totally opposite to the reality of that person. If we don't know all the aspects of that person, it is better to do not pass a judgement about him.

Because after passing a judgement about someone we always see that person in the frame which we frame and find difficulty to accept the reality of the person, so should not judge anyone.
If someone you meet is rude to you it doesn't mean that person is always rude with every one. may be today's day is bad for him or he have any argument with someone, that's why we should 1st understand the over all circumstances.
"You just never know what's going on in another person's life"
"You just never know the entire situation, the circumstances. that are involved".
"You just never know what's going on in another person's head". So it is better to do not pass any judgement before knowing about that person properly.