Say that you are invited over for dinner to somebody’s house: when is the proper time to leave? Perhaps there are those who, in not really wanting to be there in the first place, try to leave after the main course but before desert thinking they have fulfilled their obligation to “eat dinner.” There are those who will stay for desert but then skedaddle not staying for postprandials and taking pride in the fact that they stayed for the entirety the request. There are those who will gladly stay for a digestive and thank their hosts for a wonderful evening. Then there are those who will simply not go home even after the host has put on his pajamas.
Mass is much the same. Citing pre-Vatican II rubrics there are those who leave after Communion because they have fulfilled the minimal requirements of getting there in time for the Gospel and staying through the reception of Communion. This is particularly prevalent in parishes that have poor parking lots with minimal exits to busy roads. There are those who will not stay for the closing song since, “It really isn’t part of the Mass.” There are those who will stay and offer a prayer of thanks to God for the graces received and perhaps stay for donuts and/or conversation with parishioners. Then there are those who will not go home.
So when does Mass end? The final rubrics in this part of the GIRM (paragraph 90) say four things make up the concluding rite. (Note that the Prayer after Communion is not part of this because, as you can tell from the title, it is part of the Communion Rite. These four points immediately follow.
ONE: With heavy heart I report that the first is “any announcements” but stress the second part states, “should they be necessary.” And really, how necessary are they? (I know, I know - get over it.)
TWO: The priest’s greeting (the Lord be with you) followed by the blessing.
THREE: The dismissal, “So that the people may go to continue doing good works, praising and blessing God.”
FOUR: The reverencing of the altar (when the priest kisses the altar) followed by the profound bow (or genuflection if the Blessed Sacrament is in the sanctuary.)
That’s it. So technically you have fully participated in the strictest requirements of the Mass if you stay for the bow or genuflection. Time to hit the beach! Unfortunately for such, point four usually takes place during a hymn - and it would be rude to lead the priest down the main aisle so that you can get to your car before anybody else.
Now as a priest, I have to remember there are all kinds of reasons that people leave Mass early and they are not all owing to minimalist participation; someone at home is ill, work starts in 10 minutes, the kid just soiled himself, they guy you owe money to is in the first pew. . .
My suggestion? (This is not the official teaching of the Catholic Church.) On average, neither a borrower or a lender be. Remember this is about being in love with Somebody. When you were thinking of getting married, eating dinner with your prospective in-laws may not have been one of your top 100 things to do on a Friday night but you did it and stuck around a little after for love of your fiancé. So minimally stay for the closing hymn or at least until the priest is gone. Say a quick prayer of thanks. (Saying, “Thank you God that was awesome” is better than saying nothing at all.) And say “hello” to a couple of your brothers and sisters on your way out.
On the other hand, when all the lights have been turned out, the doors are locked, and it is you and one other person, and the priest is leaning up against his car in his bathing suite twirling his keys and he nieces and nephews crying to go to the beach, you might want to consider taking the conversation to the coffee house.