I'll add to that - I never found nicotine that addictive. Some grogginess, a little on edge, gone before you know it.
What's hard to quit are the motor memories/habits. Get in the car, reach for your ... wait no we quit that. You start realizing how many little habits you have that way.
This is the hardest part. This and being around people who smoke. You get used to those times when you have a smoke, or socializing with people who're smoking. Even just having your smokes in your pocket or something becomes one of those things.
