People can never be the same even identical twins, they must have some differences like the way they look at life. These differences are due to genetics and even their experiences in life.
Its really not fair if a human is being compared to another human being because they are both unique individuals with specific individuality which just need to be enhanced. Most parents are guilty of that, they always compare children. You would always hear statements like "why can't you be like your sister, why can't you be as smart or strong as your brother". They might not realise it but its very offensive to the children.
Children are different and unique and should be treated with respect because they are human beings with feelings too. A wrong word or attitude towards a child can scare them for life.