1. As being the main thing that got you sober!
The realizations that a) moderation doesn't work for me because alcoholism is a brain thing, and b) that I could continue to make booze my priority in life and suffer the continued consequences on my health, mental health, relationships, and finances. OR I could QUIT! which suddenly became the obviously SANE choice in a strange moment of clarity type deal during my last time drunk.
2. The main reason you STAY sober now?
Again, two realizations: a) that moderation doesn't work for me because alcoholism is a brain thing, and b) Life is much better this way. Even though coping with emotions can be harder, and I had to make radical changes to my social life, everything else really is tons better now: physical and mental health, relationships, finances, you got it. I would never throw it away, and strongly believe that recovery is the best thing I've ever done.