Helping peopkle quit is pretty satisfying- still have the odd person who says, "you got me off'em 10 years ago.
In actual fact, I, and the drugs I used, probably did very little, I suspect there is a degree of choice involved for people wanting to quit.
Having said that, nicotine is a very enjoyable, addictive drug.
Someone left a packet of L&B in me car the other day, they felt, smelt and looked gorgeous. Glad me' cigarette lighter didn't work.