People affected by obsessive-compulsion disorder are unable to control their preoccupation with specific ideas or are unable to prevent themselves from repeatedly carrying out a particular act or series of acts that affect their ability to carry out normal activities. Obsessive behaviour is the inability to stop thinking about a particular idea or topic. The persons involved, often find these thoughts to be unpleasant and over again. Many compulsive behaviours is the need to perform. Certain behaviours over and over again. Many compulsions deal with counting, ordering, checking, touching, and washing.