Question

don't judge a book with its cover short paragraph

Answer 1

it means you can't judge a person by its look or it's behaviour etc

Answer 2

    No matter how open minded a person may claim to be, everyone makes presumptions about others based strictly on first impressions. Seeing someone for only a split second, you find yourself making assumptions on that person's attitudes, personality, and character. You may tend to notice things about someone's appearance, mannerisms, features, and their company, that you may feel are grounds to pass judgement upon that person. I have learned a lot about this based on my own personal experiences in dealing with others who are quick to form an opinion about me.