I've never had a drink, and the primary motivator for me was that I enjoy keeping my mind sharp at all times. Plus, I find the loud and drinking crowd obnoxious and irritating, and I have nothing common with them. As soon as people start drinking, I leave because the resulting conversation descends into the inane.
Life without drinking alcohol is great, and I've never once regretted it. If I need to relax I go birdwatching and spend time watching birds.