Difference and change...why is this so big of a deal to the human race?!?

why is the entire human race it seems so afraid of change or difference? when something changes people go all crazy and complain complain complain about the way it used to be when the new way could be so much better. when someone is different it seems as though people shun them until that person conforms to what they can accept as "normal" and if that person never does they will always be an outcast. is that just human nature or is that how its been playing out for the last few centuries...ahem excuse me...MANY centuries since all the religious movements and wars i should say. and what are your opinions or views on change and differentiality?