The "walking dead" who smoke. They are apathetic, dead inside, who lacked feeling for others. Most of them are brisk walkers unlike the TV series "The Walking Dead" and so, they could walk pass most people with ease, such as the elderly, baby-on-stroller, toddlers, pregnant ladies, dogs on leash, and many more who don't appreciate being clouded by left-over trail of cigarette smoke.
I can never understand them. Why can't the smoking walkers just stand in a corner, smoke to their content as fast as they can in order to fill their blood with nicotine and then move along? I would have preferred if these people had farted while they walked rather than inhale their smoky waste. At least the fart was unintentional and could have happened to anyone. The smoke however is really a nagging prick.
The only explanation for the behavior smoking walkers is that their brains were dead long ago and hence they lacked thinking ability. This has been studied in the scientific point of view (Berger et al., 1998. Nicotinic receptor-induced apoptotic cell death of hippocampal progenitor cells. J Neurosci.18(17):6871 pmid 9712657).
Just a thought.