Well most pubs are full of old people so I dont go in them, I don't have to worry about kids in pubs and I'm not old enough for the other places you mentioned yet. But I don't smoke and I think second hand smoke is disgusting.
It gets in my clothes and my hair (aswell as my lungs), and makes everything smell awful!
From a purely selfish point of view, the sooner this ban comes into effect the better it's going to be.