Others are just mirrors of yourself.
Why does everyone seem to be stupid when you are in a hurry? Why can people not use common sense when you are frustrated? Why is it that people just do not consider you at all when you are stressed?
The answer to these questions is the same reason as to how you judge people - it is a mirror.
Inner reflection and understanding, a continued check in and dialogue with the self is a great way to start to have greater appreciation and understanding for others.
What you cast out, is ultimately what you reel back in.
Look for the good in people and circumstances, and the good you will find - both in them and yourself.
Whenever you judge someone negatively, you’re actually judging yourself.