I quit smoking 4 days ago and already feel fine. If methadone is a narcotic why do people continue to smoke?

Nice job. Lots of people say goodbye to cigs and don't look back, with no difficulty. Problem is, lots more have withdrawal symptoms for 4 weeks or longer. So consider yourself lucky and stay a no-smoker. Don't really understand comment about narcotics. But reason people have hard time quitting from tobacco, cocaine, alcohol, narcotics - is because they are addictive substances.
Additive effects. In regards to reasons that individuals on Methadone smoke cigarettes there is some good information here j subst abuse treat. 2003 jul;25(1):43-9.