Obsessive Compulsive Disorder
As the name suggests, OCD is the disorder characterized by obsession for repeated, unwanted thoughts or / with the compulsion to do certain things over and over again Eg. washing hands. Some people have only obsession and some have only compulsion, few have both.
Symptoms may vary from person to person as it reflects their thinking pattern. Like someone may think that number 9 is good to go, so he/she will wait until a bus having number 9 arrives, which may lead to further delays at office. Or washing hands for 10 times after going to washroom. Though that person is not willingly doing that, he/she is helpless as their mind doesn't allow to avoid that ritual. Some common symptoms include, frequently checking closed locks or light switches, fear of contamination of germs or diseases, frequently eyes blinking, continuous and repetitive thoughts about some events and urge to put everything in certain way, lined up or symmetrical or uniform.
Though it is not a life threatening condition, it may turn an extremely productive person into an anxious, restless and unproductive being unable to even get ready for work. Early diagnosis can completely reverse back the condition.