Some people can quit. I did and I had it bad. Over two packs a day when I quit. Some people, like my Uncle, tried everything. Cold turkey, patches, gums, nicotene replacement devices, hypnosis, perscription drugs and none of it worked for him. I know other people, who like him, have tried about everything under the sun to quit and just can't kick it.
Why can some people kick the addiction and others can't? I don't know but I do know this, it's not a failure of character on their part and that's what bothers me a lot about some of the comments of "Well everyone knows cigarettes are bad for you.". Well no kidding but for a lot of people who get hooked, they play hell trying to quit. Some do, others can't and they die due to that but it's not due to some flaw in their character. It's because they became addicted to a deadly drug and were unable to become "unaddicted."
The fact that many who become addicted can't quit is a pathetic excuse for not holding tobacco companies accountable for the millions of people they have systematically killed.