I totally agree with you. I have come to realize that most priests and bishops have no idea how many of their brethern in Holy Orders are messing with the Mass. I can understand a priest making an error. We can all make mistakes. What I cannot take is priests deliberately making up or changing the prayers as they go along. What is it that makes them think they can disobey the Church, the Pope, and so disobey God? Do they not realize that they will answer for their arrogance, eventually? Do they not realize that they are also abusing their congregations, since the Church has made it clear that the laity is entitled to an authentic liturgy - which means a liturgy exactly as directed by the Church?
I do not go to Mass looking for mistakes or deliberate changes done by the priest. I go to Mass to participate in the Worship of the Church for God Almighty. I have a Missal and I follow it - because following the written word helps to deepen understanding of what is said. Unfortunately, it shows clearly when Father Ad-libby ad-libs. Yesterday I went to Mass in a chapel I do not frequent. The Mass was celebrated by a priest I can recognize but do not know. He had me hunting in the missal to try to see what Mass he was celebrating - even though knew, since he was wearing red vestments and had announced that it was St. Justin Martyr! Why? Because the opening prayer he “read” had a first half that was nothing like what was in the Missal! When he started the Eucharistic Prayer, I was checking to see which one he was saying, and could not find it at first (it was the 2nd one - the commonest one read in my diocese) - because he had totally changed the start of it. When a priest does things like this they cannot be missed, unless the hearer has no clue what the prayers of the Mass really are. It is not being a liturgy police. It is being a faithful Catholic who has zeal for the Liturgy and is being abused by priests.
Why cannot our priests practice the virtue of obedience - to the Church, the Pope and God? Why will they not “Say the Black, do the Red”? Pride. Arrogance. Disobedience. And we should be thankful for that???