I drink/drank because it made me feel better or different. If I was happy it was a great way to celebrate, If I was sad it was a great way to forget. If I was mad, insecure, lonely, or any other feeling you can imagine it accompanied it well. Until of course I was drunk even then apparently I liked it because given the choice I'd just keep drinking. But then the next day...
When I drink unlike some people I loose the ability to be rationale to make any kind of reasonable choice. I'm never the one to say "okay, time to go home" I'm the one saying oh, come on one more bar, beer, shot etc.
If I had to say the number one reason though, it would be that I'm not very comfortable with myself sober.. and this, I'm going to try and change....