There are tables for 4, 8, 10 and 14. I think there might be tables that seat 6, but not sure.
My family is not to outgoing, but one of the most pleasant parts of the cruise is meeting other people. I know that it is risky business, but you can sure make some new friends. We were at the table for 14 once - 5 different families (4 families of 3 and one couple). It was fun getting to know everyone. We tried sitting next to different people each evening. We all did different things through the day and we shared our experiences - what a great time!! Like someone else has shared, dinning with others lets us ALL practice our manners.
If you know before hand that you won't be attending a dinner (ie Palo ressies) let your wait staff know the night before. And if for some other reason you won't be attending dinner, they do appreciate it if you let them know.