Any process has pros and cons. Just like any food can be both poison and medicine. It all depends on the measure, time and task.
Sadness is a state that occurs in the process of saying goodbye to something or someone, or the imminent possibility of such a goodbye.
The process of smoking is it is a kind of meditation in which several senses are involved.
In a normal state, a person's consciousness is filled with many superficial thoughts emanating from immediate tasks, reactions taking place outside. And access to deeper thoughts and understandings is closed in principle. A person is attached to a variety of plots of everyday life, rituals of actions. He is not up to understanding himself and the world.
When a person smokes, then, for two reasons - concentration on the smoking process and the effect of a lack of oxygen in the brain due to smoking - there is a temporary disconnection from everyday plots and superficial thoughts. Consciousness becomes accessible to deeper layers of understanding of what is happening. They may not be realized, because the person himself has no such intention (after all, he decided to just smoke), but at the level of sensations they come to the surface of conscious perception.
The appearance of a state of sadness after the process of rare smoking (as a process meditation) can (precisely "can" as an option) arise from a person's feeling of what is actually happening in his life or in the world around him.
Now the world has entered an era of changes. Everything changes and the changes will be strong. You may well feel it, but not be aware. And sadness will be as a manifestation of farewell to the old, familiar world.
Or, some strong changes are long overdue in your life, but you do not realize it. Then sadness will be the result of parting with the usual life, with some person, with some interest or occupation.
Briefly: Sadness is a farewell. The smoking process is a meditation during which you feel something that is not available to consciousness in the normal state.
Alternatively, this can be explained by the negative impact of smoking on the body. Tobish the smoker, one way or another, realizes all the harm of this habit, but subconsciously pushes him deeper, postponing the solution of the problem until later. Having given up the habit, all the secret doubts and desires of the smoker emerge. When returning to her, he again turns to them, which in fact leads to a deterioration in mood.
Such conclusions were made not just like that, but based on research results. The first series of tests for the level of anxiety and depression were conducted a week before the start of the smoking cessation process, and then repeated at 2, 8, 15 and 28 weeks from the beginning of the process.
The results allowed scientists to assume, not without reason, that quitting smoking is a common misconception that has no practical basis. And the same studies have shown that the opinion that smoking is the best way to "escape" from stress is also a myth. Source: https://ne-kurim.ru/articles/vlijanie-kurenija-na-nastroenie/
I have never dug so deeply. I smoke myself, too, not every day and I can say that strange thoughts do not take hold of me))) And since you and I are a man, it means that it’s not about nicotine influenced us in the same way, but rather on the process itself. So the fact of smoking itself affects you, and not chemicals, as it seems to me)