Caffeine is a real drug and it's really addictive just like morphine, nicotine, etc... it's highly addictive, and can even be dangerous... I'm actually getting over a big caffeine addiction; it's not fun, I was drinking 6-7 energy drinks a day, and 2-3 cups of tea... I've had a splitting headache for 4 days straight after stopping drinking caffeine, it hasn't been fun, the only way to make the headache go away is to drink lots of caffeine and I wont do that, I also can't take medicine like advil or aspirin because those contain alot of caffeine as well (caffeine is used to relieve headaches, but I'm getting over an addiction to it and I can't have ANY). It's better not to be to reliant on caffeine for energy but instead just eat right, get enough sleep, and exercise (yes, believe it or not, exercising can actually give you energy).