I believe Our Lord put us in a physical world because that is the way we could experience life. (This life, that is.) We are therefore subject to things in the physical world, from the forces of nature to the actions of others. Some people make terrible choices, such as striking out against others. The Lord does not want this to happen; people choose to sin. He lets us continue to live so that we can have a chance to try not to sin, to fight temptation, to repent and freely participate in his love. I'm sorry if that sounds simple. This is how I see it.