The best way to quit bad habits like smoking

There is a hormone in our body called endorphins that is released when we do something to the end and makes us happy and motivated to do it again. You have probably heard the term a lot that when we do something to the end and succeed, I say I lost my tiredness. This is the endorphin hormone.
So in bad habits like smoking, in order not to secrete this hormone, we should do that wrong habit halfway, and in good deeds, for example, when we determine for ourselves to read a page of a book one day, we must do it to the end.
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The second point is that we do not change any habit, good or bad, suddenly and try to do it very step by step and slowly but steadily.