I gave up 'cold turkey' about 10 yrs ago after smoking for 40 yrs.
I had to have a laryngeal biopsy under GA and was told to not smoke during the preceding 48 hrs.
On discharge I was told to not smoke for the next 48 hrs. By coincidence I had just run out of rolling baccy and our regular booze & baccy trip to France / Belgium was cancelled.
So I stopped. It was hard and traumatic but I did it. After about 5 or 6 months I went berserk. Had to stop my main hobby as an official as I had nil tolerance. The girl-friend would not get in the car with me as I was driving like a maniac and screaming at road-users an pedestrians alike. Eventually it dissipated and I became sweet and lovely again.
So pleased I stopped. Huge financial gain and feel much better as well. Did put on some weight though.