As much as we think we are the center of the universe, it doesn't make it so. After all, we see things from our own perspective ONLY. We make judgements based on our own knowledge. Our understanding is based on the facts we possess and our own comprehension. It's natural that we view all of life as it relates to ourselves.
We have to learn that though we are all individual and unique, we are meant to be a part of a body. For instance, the 23rd Psalm illustrates how God relates to us as individuals: "The Lord is MY shepherd. I shall not want. He maketh ME to lie down in green pastures. He leadeth ME beside still waters.... etc.
Ephesians 4:11-13 explains how individuals are part of a body: "It was he who gave some to be apostles, some to be prophets, some to be evangelists, and some to be pastors and teachers, to prepare God's people for works of service, so that the body of Christ may be built up until we all reach unity in the faith and in the knowledge of the Son of God and become mature, attaining to the whole measure of the fullness of Christ."
I think this is why God allows you and me to deal with Parkinson's Disease. Because it prepares us for works of service, so that we and the body of Christ may be built up until we all reach unity in the faith in the knowledge of the Son of God and become mature, attaining to the whole measure of the fullness of Christ.
Jesus learned obedience through the things He suffered and you and I are no different. Suffering teaches us! We will not always suffer with this disease. But while we do, let us learn well the lessons that God would teach us, and be mindful that we are one of many.