There is a huge gap in the study of human behaviour, and so once again having spotted it I will attempt now to write the definitive text. There is, as I'm sure you can imagine, a huge advantage to going first because you are automatically the definitive text until someone else comes along. The behavioural activity I've identified? Messing with your food.

The most common form of this is the removal of certain items from ordered food. While this has been common for years in restaurants people have become bolder recently and now tend to favour asking for the dish to be prepared without the offending foodstuff. However simply observing somebody removing food does yield something. It points to fussiness rather than obessiveness. The obsessive will tend now to check the menu and the waiter. Although many obsessives are shy and will therefore judge it to be less of a scene if they pick things out than ask someone first.

The other common type of messing with your food is the sharing of food. Some people will not share at all. They don't want anything and won't give anything. The second, and more odious type, will gladly accept things to try but will not give you anything back, and then there is the full sharer. Now within full sharer there are subsets concerning whether they demand your implement which they then supply you with some food, or they allow you to actually take your own sample or they cut a piece which they allow you to collect from their place, or they cut a piece which they deposit on your plate, or they give you their implement with the sample already loaded on it. What these types mean is complex but it is always important to remember your relationship with the person. Passing the implement is more usual among partners.

We'll pass over my father's habit of creating faces with the scraps left on the table as it is beyond analysis.

And I'd like to end with something I observed in a restaurant. A couple looked as if they were exchanging food samples. But when I looked more closely they were actually picking things that they didn't like out of their food (one mushroom, the other cabbage) and they were exchanging them because clearly the other person liked the undesirable items. Watch out for tricks like this in your observations!