Hair of the Dog
Back before we had a treatment for rabies, you had to catch the dog that bit you and put a bit of its hair into a potion. The thinking was that having a little hair of what caused you pain could magically cure you, kind of like a day-after flu vaccine. Magical thinking prevails in the advice that a shot of alcohol in the morning will cure a hangover (Carrie Fisher’s alcohol soaked memoir is titled, “Magical Drinking”). Hence we say, “hair of the dog” when we repeat an action in miniature that got us in trouble the night before. In actuality a heavy drinker would be better off drinking water (they are usually dehydrated), and seeing a counselor (any hangover is a sign of a toxic relationship with booze), rather than taking something that delays their reentry to reality.