That's definitely a factor when you're trying to give up a strong nicotine addiction.
It's not so much that nicotine addicts are weak people though - it's more like they're trapped by a morbid fear of being without the drug, and the weakness rears its head when you try to get over that fear. It's like the drug gets inside your defences, then turns them all off.
Everyone in that situation really just needs a little push to remind them they're stronger than that, but it's different for everyone.
Some people need a lot more convincing that their life will be better with more ready cash, no evil-smelling clothes and/or breath, better lung capacity, less rapidly-aging skin and -- possibly most importantly -- being able to say goodbye to the joyful fun of the constant "when and where the next cig will be smoked being foremost on the mind" experience.
All in all I'm glad I need no longer confess to being a smoker. YUK.