Although differences influence in the rising of conflict, I dont think is the main reason. I remember when I was in school and all the things that happen and how they would escalate into this big problem and argument and that was the most depressing thing, I would look around and there were 22 people in a classroom, in terms of Race, Religion, Social Class, exactly the same... and if those 22 people with no substantial difference between them couldnt get along, how will the world ever be able to? I think the real root for this kinds of problems to arise is selfishness, this is what causes intolerance, this is what causes greedyness, this is what causes a desire for power. If you are constantly putting yourself ahead of everyone else, there's always going to be a problem, people dont like middle points and to compromise and the common good is nothing more than an idea. Sad, but true. ohh and I dont think "rich and powerful countries will always have enemies", I think rich and powerful countries ARE the enemies...
ppl will alw want to fight, call it wars or some other names but that's why we can alw fight for peace.... i'd like to live in peace and many more ppl too but not all of us our interests clash and this results in what we call wars