I knew a guy from college who only smoked cloves. Smoked at least a pack a day of them.
He was very intelligent. Well spoken. Very nice guy. But he could not wrap his head around the fact that he smelled really bad, all the time, because of the cloves. He was nose blind to it. And he stunk.
I worked a job where he was a contractor and didn't get hired full time because of all of the complains of his smell. I tried to talk to him about it several times, and he just refused to listen.