I think it's all a mindset. When I first started smoking, I'd feel hazy for a little while afterwards, and seemed to occasionally make some pretty incoherent statements. As I kept smoking, and it became a pretty regular routine, I finally started settling into this mindset and developed a somewhat classic stoner personality. (I'm waaay more optimistic about things now, and I worry much less.) Now, when I go a few months without smoking, I get that same awkward feeling that I used to get when I first started. My thinking become less clear, if that makes any sense!