Our earthly selves are constantly in opposition to our spirits. By overcoming our earthly nature and through serving others we grow spiritually. Our most severe challenges will one day reveal themselves to be our greatest teacher. We need negative experiences as well as positive experiences on earth. Before we can really know joy, we must know sorrow.
Fear is the opposite of love.
We cannot truly love God or others if we fear them. The physical body can be a limitation during our spiritual development on earth. God never gives more challenges in life than can be handled. Rather than jeopardize someone's spiritual progression or cause more suffering than can be endured, God will bring that soul home, where they can continue progressing. Suicide can harm the web of connections of people on earth, possibly drastically altering the lives of millions.