The Abstinence Commitment Effect or ACE is written about in the RR book. For me it's a feeling of confidence and security in myself. It's hard to describe, for example when I was out last weekend, I was around people drinking and it didn't faze me in the slightest, I'm totally at ease around alcohol. The feeling comes from the my core, and it's just a feeling of being comfortable in my own skin and a feeling of freedom. The obsession is gone and there's peace inside me now. It's hard to describe though.
I'd be interested in hearing others experiences of the ACE effect too.