Why do people argue to be right?

Humans are born with a mildy caring nature and an urge to be right , for example a good guy sees another guy doing something wrong , so he goes right up and corrects the guy so no future mistakes are made. Another way of seeing things (if you want) at a worst angle , Muslims and christian have been arguing due to the fact that they both think they are right , christians say " There is only one god , god loves his white children , the black ones are impure humans who have commited bad deeds in their lives etc." Muslims say " all men are equal , god made us so, Allah is the one and only almighty etc. " What people do not realise is we are both right , only by believing in ourselves can we strengthen ourselves! I mean , who would just think "hey life is boring there is nothing else around us..." all the time when i do something risky , i pray. i realise this answer is going somewhere else. but when people realise that they are both right , its just one is more wrong than the other!(religion aside)So my answer is this ^