In Western culture, when you are invited out to eat at a fancy restaurant, there are some rules to remember. Here are a few:
You are the guest so don’t ask for a doggy bag at the end of the meal.
Unless your host does it first, don’t order alcohol or smoke at the table. 
When eating, chew quietly, with your mouth closed, and don’t speak with food still in your mouth. Sip soup, don’t slurp it, from the spoon.
Don’t put your elbows on the table. If you can’t reach something, ask someone to pass it to you. Don’t stretch across the table.
If food gets caught between your teeth, leave the table and find a mirror – don’t try to remove it with your tongue while still at the table.
Avoid politics and religion as conversation topics and don’t take or make calls on your cell phone while at the table.  
Finally, never spit bad food into your napkin; place it on the edge of your plate and try to cover it with some other food from your plate.