OCD sufferers will often create rituals to help ease their intense and unbearable anxiety.
Some people will feel the need to always wash their hands for fear of germs as in the case with a sufferer of Germophobia. Some people will need absolute order & symmetry in the things around them to such a degree that it begins to affect their well-being. Others may feel the need to compulsively check things like light switches, locks, stoves etc. These people will doubt their previous actions and question if they properly checked the appliance or switch., therefore compelling them to go back and check again.
Compulsions tend to fall into checkers, counters, cleaners, Doubters & sinners, arrangers and hoarders.