It is a common phenomenon that some smokers, after trying many times, eventually admit their failure in quitting smoking. Similarly, there are people who can never succeed because they easily get attempted and give up.
Some smokers do have a will to quit smoking. However, they cannot resist an offer of a cigarette by their friends. They even smoke by themselves just because they miss the smell of cigarette. As a result, they may never succeed in quitting smoking. Similarly, one could hardly succeed without a strong will to resist attempts.
Besides, some smokers, after no smoking for a short period, find no smoking is too difficult in their daily life, and then resume smoking. Some people may easily give up their plans due to slight difficulties. It is natural that these people can not get to the road of final victory.