Day after day, habit alone leads countless souls to reach for a cup of joe when their bodies are ill-prepared to face the world, hangover or no. Alas, it's not an all-powerful lifesaver. It'll wake you up at least temporarily and may even soothe that insufferable headache (if it doesn't give you one). But there's some disagreement over the appropriateness of downing caffeine an eye-opening stimulant and a diuretic when you're trying to recover from too much alcohol. Some say coffee could further dehydrate you, while others argue that's an overblown concern. Of course, it's not actually a good idea to mix alcohol and caffeine.