Obsessive-Compulsive Disorder, according to the textbook, is similar to having a song stuck in our heads. People suffering from OCD's brains contain "persistent ideas, thoughts, or impulses that are unwanted and inappropriate and cause marked distress." These extreme obsessions lead to the compulsive behavior of repeatedly doing something. Possible rituals people with OCD struggle with include repeating touching of objects, performing tasks in specific ways every time, repeated arranging/rearranging objects.
This video displays just on case of OCD. Other people suffering from OCD act differently. Rather than obsession of washing hands and staying away from germs, some might repeatedly touch objects before grabbing/moving them. "One patient", regarded in the textbook, "spent 15-18 hours per day washing his hands, showering, getting dressed, and cleaning money."
However many people suffering from OCD still find they can be successful. Famous celebrities like Cameron Diaz, Billy Bob Thornton, and David Beckham all suffer from this disorder and have found high levels of success.