Don't drink on an empty stomach: the main point of the refreshment is the enhancement of food. Don't drink if you have the blues: it's a junk cure. Drink when you are in a good mood. Cheap booze is a false economy. It's not true that you shouldn't drink alone: these can be the happiest glasses you ever drain. Hangovers are another bad sign, and you should not expect to be believed if you take refuge in saying you can't properly remember last night. (If you really don't remember, that's an even worse sign.)