I think it's saying that if just even one person cared the world would be a better place and that if maybe everyone cared it would be an amazing place with murders and no deaths (even though that's not possible.) and if no one lied we wouldn't have to be careful of everyone and spend our time worrying that they could be lying. And if we just swallowed our pride and did the right thing the world could be a better place (I sooo love this song and I looove nickleback the rock like a rock-star.)