On this subject, we have been very fortunate to have wonderful table mates and the surprise of "who are we going to get?" is as fun as the cruise. Our first cruise we were seated with a family that we have stayed in touch with for several years now and probably will know them forever. On our next cruise we were seated with another family that spoke little English, but we learned a lot about them and their country. The next 2 cruises we sat with Dissers that we became best friends with from dismeets and several after we were onboard (who are on this cruise too!) And on the last cruise many of us table hopped. It was so much fun learning what everyone did during their day and getting to know new people outside of our circle of friends.
Our first table mates told me that
DCL does an expert job of matching people to "like" people (professionals, kids/no kids, ages etc.) I don't know if that is true or not, but we've been very lucky in this way.
So, for those of you who are unsure... throw it out there, meet new folks. That is the fun of the disboards. Everyone finds something they have in common with someone else somewhere onboard. The bigger the table the more options you have of rotating who you sit with. We had a table of 12 and each night we'd trade who we sat with and even traded other tables when someone was eating at Palo (remember the rotating dinner partners CruzdirectorKaren?) and we even had special treats sent to us from other tables (Seaulater!) Put it out there, try on someone new.

My friend's family always eats alone because they are embarassed by their children, but come on it's family environment, maybe their kids could learn from other kids.
(of course, everyone understands the romantic cruises, the quiet cruises etc.)