Everyone has some rituals that they observe without being aware of.  That said, fears are forcing a person to repeat such rituals to the point of detriment, there is a problem.

Obsessive-compulsive disorder, or OCD (Obsessive-Compulsive Disorder), is a type of anxiety disorder. 

The name of the condition itself suggest that it has two parts: obsession and compulsion.

Obsessions are persistent and recurrent driving thoughts that elicit worry and anxiety. Their topics can be anything, from the personal to the large-scale (e.g., concern for the health of our loved ones, loss of self-control, pollution, war). An obsession can also take the form of mental images or impulses.

A sufferer will try to alleviate the discomfort and tension caused by the obsession by taking action with so-called compulsions; i.e., repetitive behaviors that aim to alleviate or resolve an obsession. The compulsive act itself can take many forms (e.g., repeated washing of hands, frequent checking of one’s pulse, but also an action that seems unconnected, such as knocking on the door frame a certain number of times whenever passing through).

This condition may give rise to an endless cycle of haunting obsessions coupled with compulsions which the sufferer enacts in an effort to resolve the obsessions.

OCD is a widespread disorder estimated to be suffered by 2-3% of the general population. Expert help is sought by people whose thoughts and behaviors begin to interfere with their normal functioning, or who begin to suffer from depression, which is common in up to 80% of people with OCD.