The most obvious theme here is Do Not smoke no matter what. The best way out is through. Once you quit keep on going, it will get easier.
Secondly, your neighbor clearly is not a nice person for lack of better words. You cannot change another adult, but you can change your reaction to nasty people. Ask yourself, what did smoking that cigarette do for you? How did you feel afterwards? Did you feel better? Did it fix your neighbor problem?
Little known fact among smokers, is smoking causes anxiety and frustration. Never will it resolve anything. Try and find a healthier outlet for stressful situations.
Third, try and catch your neigbor in the act. Security cameras aren't that expensive nowadays.
