DEAR MISS MANNERS: We were scheduled to have dinner with two friends at the tail end of a fun week — several days of entertainments, parties, drinking and late nights. When the day of our dinner date came up, my wife and I were so miserable that we had to cancel our dinner plans. Eating another bite of food was the last thing we wanted to — or could — do. We were burned out, and it was self-inflicted. We felt horrible for canceling on our friends, and we apologized profusely, but nothing prepared us for the onslaught of guilt and anger spewing from them, to the point that this might end our…