That's just propaganda spread by the tobacco companies. Nicotine is not that addictive at all. What, you get a few and ever fewer fleeting cravings per day for a few weeks? Does not compare to quitting heroin; 'flu-like symptoms, diarrhoea, nausea, headache, worse, you know the drill.
I know the drill from my brother in law, yep.
I, for myself, tried opium a few times when i was young but the turn almost bored me to death. I reacted very differently to it than my friends and it was easy quitting it (or not continuing, to be precise).
Well, after quitting smoking, i had the idea of getting a smoke, from many times per day to occasionally over the course of years. Whenever i was weak (or drunk) enough, i gave in and couldn't stop it afterwards (again). I needed several tries to grasp that it is addiction, not just a habit. The withdrawal symptoms are barely recognizable BUT psychologically, it's a different beast, imo.
When i realized the uselessness of smoking, i was finally able to smoke for a night and successfully stop again, a few times a year. The feeling of stupidity when smoking, like when you call up that girl you know you shouldn't ever get intimate with again, was the main reason to break my psychological addiction of tobacco. Not that i didn't suffer from these thoughts to smoke again soon afterwards, but the uselessness factor made it very easy to withstand.
Don't know about pure nicotine, but i guess it's easier to get away from it than from tobacco with its dozens or hundreds of secret additives.