I often got into trouble for asking people not to smoke in public places. When I was about 19 and used to assist my father in his business, I bought a 'No Smoking' sticker and pasted in the shop. However, it was mostly ignored and people smoked on as usual. Finally, the sticker was taken off the wall by my father because I showed it to one of the customers who was about to lit a stick.
Another time, I got up to beat up an old and rude fellow, who began smoking in a restaurant and refused to put it off. However, good for me that his friends forced him to put it off, otherwise... meri pol khul jaati :D
Anyways, smoking is one of the most annoying, useless, and harmful activities. Even Tipu Sultan, the King of Mysore and the inventor of Indian rockets, was against it. As a testimony to his distaste for smoking, he had a sign in his palace in Bangalore. Here is a pic of that.