Rav Dessler was a non-stop smoker for quite some time while serving as the mashgiach in the yeshiva in Gateshead. Once, the bachurim noticed a sign on the door to Rav Dessler's office with an announcement that the mashgiach had officially quit smoking. Mystified, one of the faculty members approached Rav Dessler and questioned him about the sign. After all, the mashgiach wasn't known for being ostentatious, so why the proclamation.
Rav Dessler turned to his colleague and replied (paraphrasing):
I know that it isn't healthy to smoke, and I really want to quit. However, I know that the urge - the taivah - for a cigarette may be too strong to resist, and I will never really quit. By putting up that sign, I'm performing a little test, to see which is stronger - my taivah for a cigarette or my taivah of pride? If people read that sign and then see me smoking again, they might think less of me for not being able to commit to something so trivial; I am confident that my ego won't allow for that...Obviously it takes a special Gadol, one whose self-awareness is intact to such an extent to make such an evaluation, but the ingenuity of Rav Dessler's strategy is amazing. Utilizing one middah against another middah can be a powerfully effective way to fix negative traits and stop unhealthy behavior.