I know I do.
When I say manners, I don't mean knowing which fork to use first.
I mean being polite about your food, and especially about your food needs.
These days, many people have decided preferences in food and drink and, in a world where anything from Trout Cheeks to Paula Deen's Deep-Fried Lasagna could appear before you, I think that's wise.
Of course you ought to try everything in this best of all possible worlds, but, even if you do, you will eventually come up with a list of Not Worth My Time (and a slightly longer list of Not Worth My Money) food and drink.
You're not a child, you're an adult. You should be allowed to eat what you want, without having to storm away from the table or produce the results of a recent urinalysis to avoid having to eat what you don't want.
On the other hand...
Just because you have taken a lifelong vow to never eat a certain food--whether your vow stems from taste, health, or philosophical reasons--does not mean that you have the right to interfere with other people's enjoyment of said food.
If you do, you are being worse than a child. You are being a teenager, for which there is no excuse in the world short of actually being between 13 and 19 years of age.
Yes, Vegetarian: this means that you have to enjoy your stir-fried green beans while watching your dinner companions rip rare, juicy beef in their teeth.
Yes, Veal-Eater, this means that you have to endure your wife's sister's new boyfriend's enjoyment of a poached salmon right in front of you, where you can smell the salmon and everything.
Yes, Ovo-Lactarian, this means you have to be polite as you watch your boss's wife enjoy a frisee salad with a fried egg on top.
Wouldn't this be a good time to re-educate your dining companions about the sensual delights and/or health benefits inherent in your own favorite foods or food philosophy? No. It would not.
But they probably have all kinds of health trouble which could be fixed by a change in diet. Really. Believe me. No.
Yes, but we all have a duty to the planet--WHADDAYA WANT, A HOUSE SHOULD FALL ON YOU? I SAID NOOOOO!!!!!!!!!!!!
Listen. The day someone says to you, "What is that very interesting dish which you are enjoying now? Please tell me everything about said dish, including why you are eating it, and omit no detail, however slight," you have my permission, and probably even that of Judith Martin, to give your "Grass-Fed Beef Will Save the World" speech.
Until then, please remember that everyone has their own preferences, and, as members of society, we are bound to nod and smile when we hear these, and save our comments for later, in the privacy of our own kitchens.
At which point, you may even speak with your mouth full.