Alcohol addiction occurs when the desire to feel good and have pleasurable feelings associated with alcohol or other drugs drives the desire to continue using the substance.
If you have an alcohol addiction you are driven by the feelings you get when you are intoxicated. You are addicted to the way the alcohol makes you feel, it's the same with a drug addiction, you need that feeling and that is all that matters to you. You continue to use and abuse the substance and you end up becoming an addict and that is when you have a serious problem.