When you engage in activities that make you feel happy. Such as a shopping spree, winning a bet, your brain gives out ‘feel-good’ chemicals that encourage you to repeat that behaviour because it provides such an exciting ‘high’. However, if seeking out the ‘high’ has developed into a compulsive and uncontrollable desire to engage with the activity in spite of the increasing negative and harmful consequences it is having on your life. Then you are dealing with an addiction.