Actually smoking becomes a chemical dependance. Nicotine mimics a chemical in the brain, so eventually the brain stops making it on its own. When the chemical is needed, we crave nicotine. It's been proven to be THE hardest habit to kick, so yes, it is that hard to quit cold turkey. It's not an obsession. It's not needed to be soothing. The brain has to learn how not to smoke. That's why there is more success in the wheening process, just like an infant has to be wheened from breast milk or formula to food. The longer a person smokes, the harder it becomes to quit.