caffeine is highly addictive. but cutting it completely out of your life could lead to some surprisingly serious withdrawal symptoms, like headaches, sleepiness, and extreme irritability. you could try buying less soda and caffeinated drinks to keep in the house, but that won't stop you from buying it at work or on the go. perhaps if you made something like soda or coffee your treat on the weekends, it could be something to look forward to. if you feel like you are truly addicted to the buzz you get from caffeine, to the point where it's ruining your life (doubtful, but i guess it could be that serious) then i'd suggest asking a doctor for advice. he or she may suggest you change/adjust your current diet. it is possible that you are not eating enough nourishing foods, which could be adding to your grogginess and fatigue, and in turn increasing your dependancy on caffeine. some people think you can drop it cold turkey, but i definitely disagree. too much caffeine can lead to serious problems, including hypertension, insomnia, and peptic ulcers! easiest way to kick this addiction? that's up to you. it's different for everyone. i found this article, maybe it could help:
http://ezinearticles.com/?Caffeine-Addiction---Kicking-the-Habit&id=280214
good luck!
參考: i had a history teacher that was addicted to caffeine, and he developed stomach ulcers before he even reached 30.