@Crazyman36 having preconception about something or someone in advance, without confronting what other things or person has to offer, limits our scope of understanding and growth. Usually, prejudice is born out of one's conditioning- the environment in which he was raised and most of all, people while growing up take loads of information from people and they analyze with their own limited brains.. and that's how one reaches to an understanding about someone or something( hence, develops a specific understanding patterns). it's something like they are wearing their own blue colored glasses and believe the world to be bluish! but they fail to consider even to look through other's glasses. prejudice could be 'cause of limited understanding or due to ego(which gives a person an impression that what he believes is the only way and ultimate truth, people like these live in ignorance for their entire existence)