I always had a lot of respect for my Rebbe, despite the fact that he was a big smoker. The level of respect shot way up when he quit smoking. He explained “how” he quit.
His Rebbe, held like the opinions that one should not smoke on Yom Tov (I am not issuing a psak, merely stating the opinion held by this Rosh Yeshiva,) so no matter how much my Rebbe wanted to smoke, he knew that his own Posek ruled no, so he did not, it was akin to eating treif. It was that much harder on a “3 day yom tov”. Nevertheless, he managed to survive without smoking. After Yom Tov, he wanted to light up. He tried to rationalize “hop he addicted he is”, “how enjoyable it is” and then he realized he lived without this “addiction” for three days and nothing happened to him. He felt that all the reasons he gave for smoking until that point, were nothing more than excuses. He simply stopped smoking. As a product of a “Slabodka Mussar” yeshiva, the gadlus ha’adam told him, stop giving into this naarishkeit. And he did. Cold Turkey. He stopped smoking about 3 minutes before Shkiya one Erev Yom Tov and never resumed.