I enjoy drinking a very strong black coffee. Whenever I feel down, a cup or two will fuel me up...

Much better than Desoxyn...

trying to get down from 21 cups / day to something normal. Bad thing is that the body acts up. Any idea how to get over that?

I have a caffeine addiction and I get nasty headaches as withdrawals. They usually come if I haven't had any coffee during the day which is very unlikely these days and I usually drink at least five cups per day, sometimes more.
In addition to that, I drink a lot of coke-like sodas, Pepsi Max being my favorite. I can't stand "normal" sodas since I've been drinking light-versions for so long that they feel like syrup in my mouth...
Oh yeah, I like energy drinks, too. Monster and Pitbull are the best!

As a side note, I've been drinking coffee ever since I was one. That's 20 years. Woot.