In general, the symptoms of OCD fall into two diffrent but related groups: obsessions and compulsions. Obsesions are repetitive, unwanted, often unpleasent or upsetting thoughs that and some times "stuck" in your head. Compulsions, are ritualized, repetive behaviors usually designed to relieve the anxiety caused by the obsessions. But, the relief is very temporary, the obsessions return, and the long-term suffering returns. It has been said that doing the obsessions cause the OCD to become worse.
A person with OCD may have either obsessions or compulsions alone, but the majority of people with OCD experience a combination of obsessive thoughts and compulsive behaviors. For example, a person who is afraid of his or her house burning down, may feel they have to check things to make sure they turn the oven off.
People with OCD often realize that their thoughts or behaviors seem senseless or irrations but still people feel compelled to continue to continue doing the obsessive and compulsive behaviors.