I like to get a little out of it now and then, but I don't like to get too out of it too much, and thus my rule is to do as little as possible of any intoxicants, including caffeine. I do tend to do too much, though I don't beat myself on the head for my excesses. I just pick myself up and keep going.
I see the precepts, including the fifth one, Refrain from taking intoxicants, as warning signs around certain areas of conduct—not absolute commandments but flashing lights suggesting we be careful and wary. We don't want to hurt ourselves or others, so we should take heed.