It's not about hate, really. People just want to do their own thing. So, if you ever got to a point where things were one world, one government, you'd quickly have people grouping together who wanted things to do things a certain way, and once they were all together, they'd demand sovereignty so their laws could reflect their beliefs, etc.
And thats what I have to say. Of course, it would be great for frontiers to fall, I'm all for it, but it seems quite impossible. Maybe someday, it would be nice, but of course, if the world was united, it would need to be under no goverment, or something like that, and frankly, I don't see that coming.