The challenge for Kant was serving lattes. In his late teens, while training to be a barista, he learned of the potential dangers from improperly handled milk. He became obsessed with the possibility of harming customers through inadvertent negligence. Even worse was the prospect that he might never know.

As part of my harm obsession, one of my concerns is that germs from my mouth will hurt others. Although I try to keep my fingers away from my lips and their germs while I’m eating, I’m rarely successful. By the end of the meal, I believe that my hands are contaminated. The problem is that I need them to scribble my signature on the check.

If I’m lucky, I will have remembered to bring my own pen; if not, I may feel compelled to wash my hands. Forget drying them, my napkin would only re-contaminate them.

Once the check is signed, I must be sure that it is really signed. At my worst, I have opened and closed the vinyl check holder again and again, seeing my signature each time, yet unable to feel certain. I’ve left the table, only to return to check again. And again.

Help is available, in the form of a therapy called exposure response prevention. The technique calls for exposing people with obsessive-compulsive disorder to situations that trigger obsessions, then preventing them from acting on them. The therapy addresses low-level anxieties, and works up from there.

With restaurant cleanliness, for example, a therapist might have a client rate his anxiety about challenges ranging from simply touching spotted silverware to eating from a spotted plate. Then the therapist would ask him to face those situations while fighting the compulsion to clean or replace spotted items.

... contd.