When is Smoking Unethical in the Army?

I am a smoker and I smoke whenever an opportunity presents itself, whether in civilian clothes or in military uniform. I don't consider my smoking as bad, undisciplined, ungentlemanly, unpleasant, unhealthy, or vexatious to others. I couldn't care any less of what others say about my smoking since I buy my own cigarettes from my very own money, believing that I have the right to dispose my income to whatever that makes me relatively happy without having to affect others directly.