"Thinking is difficult, that's why most people judge." -Carl Jung
What is meant by this and why is it important? From my perception and experience with my own ability to think, I see the question as, "do you think for yourself?," or is your thinking not thinking at all but a series of conditioned responses you learned from your parents, opinion leaders, taste makers, religious leaders, movie stars, teachers and society at large? This means that when you don't think for yourself, you parrot back what you were told and there isn't an original thought in your reality. When you are a conditioned robot and don't think for yourself, you are at the whim of self-judgement and being judgemental of others because you are coming from the lower ego of "eat or be eaten." This is a state of ignorance and fear. You are in prison. You are in a cognitive trap and can't think for yourself.
This makes you an unwitting and easy pawn.
If you believe it's important to think for yourself and know exactly how you feel about something, the first step is to ask yourself how you feel about what you think about something. Is it your thought or the thought of society? How do YOU feel about something? This is the beginning of learning how to think for yourself as you begin to get in touch with how you and you alone think and feel about things and not what your church, temple, synagogue, mosque, school, teacher, parent, friend or government told you to feel. This is the beginning of separating yourself from the opinions of others and what your real opinion is and this is solely for the purpose of seeing that judging is the only thing you can do when you don't think for yourself.
When you have your own, real thoughts, created by your own understanding and reasoning, you can bring fresh perspectives to the world and be an opinion leader not an opinion follower.
This takes a lot of soul searching, work and practice to learn how to think for yourself. Why is it worth it? So you can stop being a slave to others' thinking and judge as you would be judged.