OCD is a disorder where people have constant and repetitive thoughts, sensations, feelings, or impulses (obsessions) that they alleviate by performing tasks, rituals, or certain behaviors (compulsions). Common obsessions are contamination, hurting oneself or others, or cause of a catastrophic event among others. People with OCD feel like if they do not carry out the compulsions - counting, hoarding, ordering, checking, or performing another routine - they will allow their obsession to happen.
OCD interferes with daily life because those suffering from it need to carry out these rituals. It can cause them to miss important events, interfere with social relationships, and in severe cases consume them completely. The fear and anxiety associated with missing a routine can be debilitating as well. Therapy can help to manage these obsessions. It may take time to eliminate compulsions from your life. This is done incrementally, maybe removing one step from a routine at a time to show that there are no consequences with not doing something. Your therapist can develop a plan of action to free you from your compulsive behavior.