I love my Starbucks Doubleshot Espresso & Cream's, I usually have one a day, sometimes two, and I feel really good when I drink one. But I don't know if it's the taste or the caffeine that makes me feel good. The feeling comes instantly, and it doesn't make me feel extra 'awake' or active or anything, which is why I think it's probably just the taste. If I don't have one I sometimes really miss it but I don't think that missing feels like withdrawal. Though I've never been addicted to any (other?) drugs to compare it to.