I'd like to introduce into the lexicon of restaurant discourse two serious conditions that afflict several members of my family.
First of all, my brother, ever since he was a very small child has been suffering from Restaurant Restroom Syndrome (RRS). Those afflicted with this condition must always visit a restaurant restroom at least once, and often several times, during a meal. Those with RRS may not even be aware that they have this condition, but when informed about the diagnosis they are powerless to change their behavior. Long-term effects of RRS include feelings of bemusement by other members of the dining party, who may well snicker, "RRS strikes again." There is no known cure for RRS.
Second is REFS, Restaurant Entrance Fixation Syndrome. Simply put, one who suffers from REFS must always face the entrance of any restaurant he or she dines in. I believe this is a more common malady than RRS, but no less serious. Often, the sufferer of REFS, in this case my mother-in-law, will require several tables be presented by the restaurant's host or hostess so that she can evaluate which one offers the least obstructed view of the entrance. In restaurants that are so arranged that no front door view is available, the REFS sufferer will (based on the severity of the case of REFS) either refuse to eat at that establishment or choose to sit so that he or she can see at least close to the entrance of the restaurant. Effects of REFS include severe annoyance on the part of the diner’s companions. Theoretically, REFS can be treated by use of restaurant entrance deprivation therapy.