The Gospel is simple, and praise God for it. Yet, many preach false gospels, and many who even affirm the true Gospel at face value don't affirm it on God's terms. An altered gospel is a false gospel. It's God's Gospel, therefore man has no right to change it or reject it.
"Every service is a structure of acts and words through which we receive a sacrament, or repent, or supplicate, or adore. And it enables us to do these things best — if you like, it “works” best—when, through long familiarity, we don’t have to think about it. As long as you notice, and have to count, the steps, you are not yet dancing but only learning to dance. A good shoe is a shoe you don’t notice. Good reading becomes possible when you need not consciously think about eyes, or light, or print, or spelling. The perfect church service would be one we were almost unaware of; our attention would have been on God."