On Thanksgiving we give thanks to God for all of our blessings. We express gratitude for our material belongings, for our family, for our country. Before the feast, we thank God for this food and the hands that prepared it. That is to say, Thanksgiving is about vocation.
One of the most important teachings of the doctrine of vocation is that God works through human beings. He distributes His gifts by means of ordinary people carrying out their vocations in the family, the workplace, the church, and the community: giving daily bread by means of farmers and bakers; creating new life by means of mothers and fathers; protecting us by means of police, soldiers, and the legal system; healing us by means of medical professionals; giving us the benefits of technology by means of scientists, engineers, inventors, and factory workers; making works of beauty and meaning by means of artists; proclaiming His Word by means of pastors; etc., etc. And just as God blesses us through the people who do so much for us, He blesses others through us. When we love and serve our neighbors, which is the purpose of every vocation, God works through us to bless others.