I quit smoking and got on the nicotine lozenges. I was eating a bunch of lozenges, almost constantly. Then I started kinda smoking again, but didn't stop the lozenges. Then I had a stroke which left me with a permanent disability, likely partially caused by wild blood pressure swings due to high levels of nicotine.

I quit by default after 3 weeks in a rehab center. The lesson here is... quit before the hospital. It's worth it.