ok guys, cool down a bit please, this is a good discussion and i dont want it ruined by hot headed comments. Use intelligence to win your internet battles, not petty playground comments.
back on topic:
we will never live in a Utopian society where we are all joining hands and singing.
Every culture has it differences, its these differences that cause clashes with other cultures.
Religion
Politics (governments in power)
"Fighting the good fight" (war against "terror")
Energy (the future reason IMO)
Our civilisation goes round in circles, build up of tensions, something breaks out, things are sorted out, we develop as a civilisation and evolve our cultures.... then someone else pulls on the lions tail and it happens all over again