Don't Judge A Book By It's Cover??

"Don't judge a book by it's cover"

I am totally disagree with this sentence when it comes to a situation where someone evaluates you! "They" really judge you by your appearance. I feel this world is totally unfair. I thought the evaluation is based on how you speak and how you present yourself. However, there is this kind of people, who judge a person based on how pretty you are! Why on earth there is this type of people exist! He said, "I will only judge based on the way you speak and the confidence that you have in yourself". Liar!!!