1. Standing up to process to receive Communion when you won’t be able to leave your pew for another 2 minutes
I don’t get it. Why do you do this? This is when we kneel in reverence; the standing and walking is strictly out of necessity. The procession should be sober. It shouldn’t look like a rush to reserve your spot in line. Hey, if you’re excited to receive the Lord, great, but how about some order and patience in the ranks, huh? Additional time in prayer wouldn’t hurt either.
2. Sitting down just because the priest sat down after Communion
Maybe you should be sitting down when the priest sits, but his sitting is not the reason for your sitting. The priest can sit whenever he wants (almost), but we don’t take cues from him. Nobody should sit until the Host has been returned to the tabernacle. If the tabernacle is not in view, then everyone ought to be waiting until the ciborium has left the sanctuary.
3.Saying the words of consecration (“This is my body…”)
Who are you? Because if you’re not a priest concelebrating the Mass, zip it, friend! At best, this is inappropriate and mildly scandalous; at worst, it could constitute simulation of a sacrament — obviously a very grave offense. The ministerial priesthood is absolutely distinct from the baptismal priesthood, and the laity have no business trying to blur the lines.