Based on my own experiences, I'm also in the simple explanation camp. I drank because I like the way it feels to be drunk. Part of my brain registers that as deep pleasure. That part of my brain is constantly telling me to drink more alcohol.
The other parts of my brain realized that the side effects of alcohol were destroying my life, so I knew I had to quit. I know I need to stay quit.
If I drink again it will be because I bought alcohol, put it in my mouth and swallowed it. A series of choices I have made many times in the past, but have decided not to make any longer.