I'd like to second this, as its under appreciated by the public at large. So many failed New Years resolutions for improving oneself can be pinned to this point.

Anecdotally:

I've been trying to lose some weight, and one of the first things I moved to do was drop drinking (as most resources on weight loss will tell you to do). It was very tough to do because I love my beer. I found the process was making me miserable.

Sure if I leave the beer out of the equation my calorie deficit would grow, but including some beer still keeps me at a deficit regardless so that I still am losing 2-3 lbs a week, and very much happier all the while then if I was losing more and more quickly.

edit: except for the smoking. That's a slippery slope.

It's all a personal choice. I'm clearing my life of things that distract, delude, lead to disease, premature death. I'm very much into Buddhism and wildlife conservation, this is the right way of life for me.

Every now and then, I indulge in some ice cream or some sushi. Slow progress is better than no progress. I know I am better off without alcohol, weed, or tobacco though.