Ah, this just made me think of one more thing... LOL...
Sometimes when I'm in a deep sleep I will actually have dreams related to being thirsty, but it never wakes me up and makes me want a drink. I have dreamt that I'm really sick and my throat is really dry or that I am so thirsty I drink from a garden hose, etc. LOL. The same happens when I drink a full bottle of water with my nightly vitamins... I will have vivid dreams about desperately needing to go pee. It also doesn't usually wake me up. Man, I must be a really sound sleeper. LOL.