I realized some month ago, that I'm a caffeine addict, and I want to share some experiences about the good and bad side of the drug.
Everything started a few years ago, when I started to drink Cola instead of other soft drinks which I'd liked before. It slowly became a habit, and I used to drink 2-3 litres of Coke (Light) every afternoon. Every time I consumed it in 30 minutes, I felt euphoria. Usually mild, but sometimes it was more pronounced. During the first times, I had mild pain in my heart, but later it disappeared, I guess because of the tolerance. Months later I used to drink milky shake with instant coffee. It had the same effects, although the calcium in the milk neutralized some caffeine.
Then there was a changepoint a few months ago, when I was at a party and didn't want to drink alcohol, so I drank about 5 litres of Light Cola and 3 mugs of coffed. I had a high: mild euphoria, slight sensory changes, faster thinking. But my heart and my head ached terribly, and I couldn't fall asleep after the party. Next day the bad symptoms had gone away, just happiness left behind.
Since then, I drink 2-4 litres of Light Coke, and 1-2 mugs of strong coffee every day. I need Coke to think normally, without it I'm always tired and unable to concentrate. Coffee is needed in the middle of the afternoons to become relaxed and happy. Coffee has some chocolate-like effect so I can't use Coke instead.
Sometimes I drink Tea made in a coffee maker. It's kicky, gives a nice buzz, less euphoria, more relaxing, probably because theobromine and stuff.
I tried to give up drinking caffeine several times, but I just had a few 'clean' days. It seems, that I'm physically addicted and it's a problem because of the heartache and the insomnia which are usual nowdays. I don't know what will happen, but I'm afraid of heart attack.
My advice: be careful with caffeine, don't drink it every day.