Since I have only been on one cruise and we had anytime dining, all our tablemates were pleasant. But I have had the experience with a "know it all" on land when we go camping. It is such a turnoff to hear this know it all tell you stories of how they saved the planet, they know everyone that is important, they know how to build everything and start using all these technical terms, etc. Luckily for me, I can walk away to my trailer and get another drink, check on my kids, etc. But if this should happen to me on a cruise, I would definitely request to change tables as you paid alot of money to get away and have a good time.