I was actually shocked recently when I realised I was probably addicted to caffeine.
I was wondering why, on my days off, that on the 3rd or so day these almighty headaches and unwell felling would kick in. I thought it was just getting over the shiftwork, but no, seems it is the caffeine I tend to drink more of when I am working than when I am at home, and relaxed.
I would drink maybe one or two cups of coffee a day at work, then if the weather's hot I'll have a can of Coke or two. But the carbonated drinks give me a bloated feeling and can upset the gut a bit, so in recent years I have backed off that stuff.
Having dodged the addiction of tobacco, and been careful not to get into a position to become alcoholic, I'm a little annoyed that the most freely available and less restricted addictive substance is the one that's got me hooked! :doh: