It is a good idea, particularly if you have several kids or even just a couple, to have a keep your body parts to yourself rule at dinner. We don't want poking, prodding, teasing or name calling. This is a place where we're all nice to each other at the dinner table. I think this is a great time to teach kids basic table manners. How do you pass food? In what direction? Say please and thank you to each other. This is a time when everybody gets to talk and everybody gets to be heard. I think those are just some good general ground rules for kids and they're good for adults as well.
Mom and Dad should remember we want to model what it is we want our kids to do. You don't have to have the Ten Commandments at the family dinner table. It doesn't have to be so elaborate but if f you set a few good ground rules for how you want them to behave, it sets it up so everybody can relax and enjoy the meal.