Coffee breeds aggression, impatience, sloppy thinking, heart disease, weight gain, and bad planning, in the form of overconfident (and therefore inaccurate) estimates of time to complete tasks. It increases the probability of insomnia, which means it increases the probability of insomnia's consequences, including aggression, hostility, insecurity, paranoia, poor job satisfaction, heart disease, bad driving, and erectile dysfunction. It also makes your bodily fluids taste bad, which means it reduces your chances of receiving oral sex. Coffee's out to kill you and destroy your penis. It's evil and you should shun it.
I found quitting coffee incredibly difficult at first. I stopped cold turkey. After about a week, the withdrawal symptoms hit me. I thought I was dying. My bones ached, I shivered uncontrollably, and I had a splitting headache. It was like Trainspotting.
I went back to coffee the minute I figured out what was going on. I am a man of iron will, impervious to any form of pain, unless it means my pain, in which case I am a man of jelly will. Or maybe I'm not. I don't know. It's up to you! Just make the pain stop.
From reading Wikipedia, though, I knew the amount necessary to alleviate the withdrawal symptoms was much less than the amount I normally drank. I never went back to my previous levels of intake; I just maintained minimal withdrawal-avoidance dosages. This was easy. It meant buying small lattes and not finishing them.
Soon after, I went into hospital for angina and had heart surgery, maybe a month before my 35th birthday. From the moment I went into the hospital, I haven't touched coffee once, except one time several weeks later when I ordered decaf at a breakfast place. (It made me wired and twitchy for hours.) I haven't had any headaches, bone aches, or other withdrawal pain. It's been easy.
To summarize, this is my method for quitting coffee:
1. Quit cold turkey
2. Experience terrible pain
4. Slink back to coffee with your tail between your legs
5. Drink much lower levels, just enough to avoid withdrawal symptoms
6. Experience life-threatening heart disease
7. Have heart surgery in your mid-30s
8. Never touch coffee again
I will admit my method is extreme. However: it works. I haven't touched coffee in a good while now, and I don't expect to go anywhere near it again ever in my life. Feel free to emulate me, and to use my method. You can leave out specific steps if they seem like too much trouble, but I wouldn't recommend skipping step 8.