We had a wonderful table years ago on Costa Riviera. One May November couple, one on their 25th anniversary, one in their 20s celebrating their 5th anniversary and Arlene and I in our mid thirties. All the couples, except for the one celebrating their 25th anniversary, had cabins together as we had all taken advantage of a 2 for 1 deal and had wonderful cabins on Amalfi deck. The other couple was deep in the bowels of the ship in an inside cabin. This gentleman (used loosely) was a braggart. He got to be annoying at dinner, but wasn't too bad; just we all started feeling sorry for his wife. He kept saying how he got such a good deal and wanted to know how much we paid. None of us would say. Finally, on the penultimate night, he got on the nerves of the older gentleman at the table so much that he told him how much we all had paid. The guy was fit to be tied and stormed out of the dining room.
I must admit, except for a short three day cruise, we have always sailed wherein we can choose our own dinner companions or ask the Maitre D' to match us up as he wishes.