As Jesus prepared His disciples to be His witnesses he encouraged them to press on, even if the world hated them. The cultural Christianity that pervades the US churches is working towards getting the world to like us, something that Jesus says is an incorrect focus. This does not mean we are to be unkind or obnoxious, but that Jesus makes very clear that the world hated Him first, and because of this, it will be in opposition to the kingdom, to real Christians, and to the Lord Jesus. To love the world is to be an enemy of God.