For them.

My biggest regret in life is starting smoking again after quitting for nearly three years. I started smoking again when I became a single mother, because the stresses I experience daily is insurmountable. But every time I smoke, I hate myself. I desperately want to be healthy again, and I want to be a better mother. I am starting my quitting journey, and I am more serious about it now than I ever have been. It is hard, really hard. I've cut down to three cigarettes a day, and I'm working towards zero. If the incentive to be healthy for myself isn't enough (which for most smokers it's not) then I'm doing it for them.