• Habits are repeated actions that must be consciously initiated. Eventually, the process becomes subconscious and automatic: for example, when you are brushing your teeth.
• Unhealthy habits can become a compulsion or even an addiction. For example, the good habit of regular exercising can become an unhealthy compulsion or addiction when done in excess.

The difference between a compulsive behaviour and a habit is the ability to choose to do them.

• Compulsive overeating is the inability to control one's amount of nutritional intake, resulting in weight gain.
• Compulsive shopping is done to the extent that it impairs the shoppers' lives, leaving them financially unstable.
• Compulsive checking describes the constant checking of things like locks, switches, and appliances.
• Hoarding is the excessive saving of items and the inability to throw away any of those items.
• Compulsive gambling is the inability to stop. It results in serious personal, financial, and social problems.

When an otherwise harmless behaviour becomes so consuming that it negatively impacts oneself or others, it may be a symptom of obsessive-compulsive disorder (OCD).

Most compulsive behaviours attributed to OCD are incredibly time-consuming, cause major distress, and impair work, relationships, or other essential functions. It can include behaviours such as eating, shopping, hoarding and animal hoarding, skin picking, and gambling.