Because adenosine, in part, serves to regulate blood pressure by causing vasodilation, the increased effects of adenosine due to caffeine withdrawal cause the blood vessels of the head to dilate, leading to an excess of blood in the head and causing a headache and nausea. This means caffeine has vasoconstriction properties.[94] Reduced catecholamine activity may cause feelings of fatigue and drowsiness. A reduction in serotonin levels when caffeine use is stopped can cause anxiety, irritability, inability to concentrate, and diminished motivation to initiate or to complete daily tasks; in extreme cases it may cause mild depression. Together, these effects have come to be known as a “crash”.[95]
Withdrawal symptoms — possibly including headache, irritability, an inability to concentrate, drowsiness, insomnia and pain in the stomach, upper body, and joints[96] — may appear within 12 to 24 hours after discontinuation of caffeine intake, peak at roughly 48 hours, and usually last from one to five days, representing the time required for the number of adenosine receptors in the brain to revert to “normal” levels, uninfluenced by caffeine consumption.
If you ever doubt caffeine’s potency, try quitting it cold turkey. When I pulled into a rest stop off the Jersey Turnpike to clean out my car yesterday and realized I had already drank about 48 ounces of coffee and a bottle of Diet Mountain Dew, I realized I should probably go off caffeine for a while. Now I have a brutal headache, and I’m quite irritable. Who wants to fight me?
Tedquarters 
Caffine ceratinly has it benefits, but I have always made an effort to not drink to much of it, and only drink it when I really need it. Only time I ever really got into a “habit” of relying on it was back when I was studying for the CPA exam and working full time.
And most of the people who “have to have thier coffee” only have to have it because the started drinking it in the first place.
Which brings me to my next point, coffee itself. I personally find it to be horrible tasting. I always prefer a soda or a redbull if I need the caffine. Can some coffee drinkers out there tell me, do you really enjoy the coffee itself? or just the caffine intake? And I’m not counting some of those ridiculous coffe drinks that taste like a milkshake or have a full bar of chocolate disolved in them.
Coffee is absolutely awesome. I couldn’t possibly stop drinking it. As for you, Mr Berg, might I suggest a gradual stop?
Just the person to answer my question above, is it the coffee thats absolutley awesome of the caffine in it?
Like would you still enjoy a coffee if it was decaf?
I find that when I’m drinking coffee regularly, I think the taste of coffee is amazing and the smell of it divine. Then I stop drinking coffee and I’m like, “holy hell, is this something you drink a dare?”
Lies. Coffee is the Elixer of the Gods.
I actually like the smell of coffee, and even some mildly flavored coffee items, like a good coffee flavored Ice cream or something, but coffee itself I just find terrible. Leaves the worst taste and coffee breath behind.
I actually like the flavor of it and I know the effect caffeine has on my body. So, if I’m feeling tired I have regular coffee, and if I just want a nice hot drink I go for decaf. I also try to never drink coffee after 5 since it makes it harder to sleep. I usually have a cup in the morning and sometimes one after lunch if I feel sluggish. I do find, though that the caffeine gives coffee a bit of a bite that the decaf stuff lacks, so some people may prefer one or the other. I’m not much of a coffee snob, though. I’ll just drink whatever’s around and I’m in the mood for. I try to stay away from sodas though, I don’t really like too many sweet things.
I hate the taste of coffee personally. Cappuccinos are pretty decent though. I only drink it though when I need to stay awake in class, cause lord knows I’ll sleep through my whole day of school without caffeine.
I find caffeine to be a placebo except in large doses.
I hate coffee, I do drink Red Bulls on occasion, and they do absolutely nothing for me.