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.