Why people are not help each other all over the world for peace till become like one country?

Some would say that people hold grudges and have prejudices. Not everyone wants to help out. People are selfish.

However, even if we all had the best of intentions, we must respect that fact that people cannot always have the same ideas. You might have one answer to a problem, and I might have a different one. Who is right?

Anyhow, if we all had the same opinions, how sad would that be? No variety in our lives? No creative tension? What meaning would love have if we never experience hate? Similarly, peace would have no meaning without war.

This is not to advocate for more war. It's just to point out, the idea of no war is an absurd abstraction.