Focus on the smell. Make it long enough (about 24 hours) to notice other smokers smell. That is the smell of other people being repulsed by you. You smell like that in every elevator, every time you introduce yourself to someone, and no amount of gum or tooth brushing covers it up. You can't smell it while you smoke, but the rest of the world can.

It was enough to keep me dedicated knowing I could confidently talk to anyone after I quit without having to wonder if they were immediately put off by my smell.

People who still smoke always complain that ex-smokers are the worst and most judgmental about smoking, and it's 100% true. It's because we feel seriously ashamed of ourselves for being so stupid for so long, it comes out as assholishness sometimes.