Having made the comment earlier about Starbuck's price increase... I should probably mention this study which recently came out to confirm what all coffee drinkers in the world already know:

In the most comprehensive review and analysis of the effects of caffeine abstinence in humans published to date, the researchers conclude that as little as one small cup of coffee daily can produce caffeine addiction.

In general, the more caffeine consumed, the more severe withdrawal symptoms will be, with some people even reporting depression, nausea, vomiting or muscle pain.
...
Griffiths stressed that coffee is not the only culprit. He said soft drinks and other products containing caffeine can produce withdrawal symptoms, including fatigue and irritability.

Duh. So what's next? Think a complete ban on caffeine is that far out? Think that there aren't some people out there that wouldn't love to try? Think again.