Some of you took part in the poll about where to leave your napkin in case you need to excuse yourself from the dining table briefly (examples are if you need to take a very important call that cannot wait, or if you really need to go to the restroom).
Well, I must say opinions vary when it comes to the place your napkin should be left at. Some experts say the appropriate place is to the left of your plate. Some experts say it is on your seat.
Here are my insights:
Leaving it on the table, to the left of your plate: A (hopefully not so) dirty, used napkin looks like it "d.n.b." (does not belong) on a table where others are still dining. Depending on how much room there is for all people, your napkin might be too close to the other person's elbow and right hand.
Leaving it on the seat: Nobody will really see or be bothered by your napkin, so that is a good thing. On the other hand, we know the seat has been sat on by more than just yourself, and before sitting on this seat, you sat on other places as well. People regard this as a possible hygiene issue.
My personal solution is the following: I will leave it on the seat. In high-class establishments, you can maybe even receive a clean napkin by the time you return. If not, don't worry. Your napkin in usually large enough to be folded in 2. I use the inside of the napkin, and thus, my lips will not touch what the seat has touched. Crumbs will be there, so I am careful and simply try to avoid them as much as possible.
Also, another good hint: If you are going out on a special date, an important business dinner/lunch and are wearing dark pants, trousers or skirts, make a test at home to see if it will possibly pick up "napkin lint" easily! Like that, you will avoid walking out of the restaurant with a clearly visible lint patch on your pants/skirt! (most restaurants opt for white, off-white, ivory, champagne colored napkins, in addition to other light colors)