Social Expectations?

Why can people not accept the way you are?

Why do people have to judge you before they know you?

Why can't people respect others that may be different from them? 

It says in the Holy Qur'an - 'We have made you amongst different tribes so you may know one another'

It doesn't say so you could fight amongst each other. it doesn't say so you could be jealous of one another. It says so that you may know and identify one another. At the end of the day, we are all different. our ideologies may be similar to some due to the environment we have grown up in and how we have been raised but we are all different. so why do people have to mock, judge, envy and quarrel with each other because of (mostly) minor disagreements? It just frustrates me.