Good table manners avoid ugliness. All rules of table manners are made to avoid it. To let anyone see what you have in your mouth is offensive.
So is to make a noise. To make a mess in the plate is disgusting. So there are some rules how to behave yourself at the table:
Do not attract undue attention to yourself in public.
When eating take as much as you want, but eat as much as you take. Never stretch over the table for something you want, ask. your neighbour to pass it. Take a slice of bread from the bread-plate by hand, don’t harpoon your bread with a fork.
Never read while eating (at least in company).
When a dish is placed before you do not eye it suspiciously as though it were the first time you had seen it, and do not give the impression that you are about to sniff it.
Chicken requires special handling. First cut as much as you can, and when you can’t use knife or fork any longer, use your fingers. The customary way to refuse a dish is by saying, “No, thank you” (or to accept, “Yes, please”).
Don’t say “I don’t eat that stuff, don’t make faces or noises to show that you don’t like it.
In between courses don’t make bread-balls to while the time away and do not play with the silver.
Do not empty your glass too quickly – it will be promptly refilled. Don’t put liquid into your mouth if it is already full. Don’t eat off the knife.
Vegetables, potatoes, macaroni are placed on your fork with’ the help of your knife. If your food is too hot don’t blow on it as though you were trying to start a campfire on a damp night. Try to make as little noise as possible when eating.
And, finally, don’t forget to say “thank you” for every favour or kindness.