In Group, Out Group

In group, out group. You can probably blame most of the worlds problems on our propensity to segregate ourselves in this way. We seem to have evolved an intrinsic mistrust of people and cultures that think and act differently to us.
I'm a repeat offender in this respect, and it's not a quality I like about myself. I don't even draw consolation from being just like almost everyone else in this regard; I feel I should know better, think smarter.
Thing is, if you subscribe, as you should, to the idea that every single living thing derives from a common ancestor, and if you accept also that the biological differences between even the most diverse humans are negligible, it should put to bed any qualms about race or colour. Humans are genetically so alike that to think of ourselves as different is just plain daft. Yet we do just that; we organise ourselves into groups, tribes, cultures, creating countless human tributaries that seem to have forgotten that we're actually still part of the same great river of life. We often mistrust outsiders, devaluing them before we ever really know a great deal. And we all do it, and it's been the cause of a lot of angst down the years. I wonder what it's going to take for us to truly accept diversity without fear? I wonder if we're even capable, if I'm capable of achieving this noble goal? What would it take for me to live and let live and genuinely mean it? To be accepting of people's differences rather than wary?
As I reflect, the best I can do is to try living my life without doing so at the expense of other people. Impossible I know, but I figure that if I at least have a go I'll make some inroads. I have strong opinions and I don't want to be so insipid that I never speak out, but perhaps there's a more sensible balance to be struck as to how this plays out? It's a funny thing being an individual yet also part of some greater entity. We shouldn't be sheep and we all have to operate in the marketplace of ideas. For my part, so long as your worldview or actions don't impinge on my liberty then you can live as you please. And as long as your actions don't cause harm, either directly or indirectly to your fellow creatures, you should be free to express yourself. Its when we seek to cross that line where problems begin; when we try to impose ourselves with undue aggression that we start to bump and grate against each other.
I want people to have rich and satisfying lives. I want to see the highest good for the greatest number. In order to achieve anything even remotely close perhaps we all have to admit that as much as we might like to, we can't have it all our own way?