(A spinoff of who influenced you ...)
Two women come directly to mind when I think of this. Both while I was living in Germany, both Americans. One was military (married to military), the other was a military wife. The first was looking for a means of losing weight, and came to me about it. I did let her know that she'd be trading one problem for another, which she accepted. Asked about a good starter brand, asked me for a few tips. Long story short, she started, lost the weight, and her husband considered me to be his heroine! The other was during the first Gulf War, her d/h was deployed to Saudi Arabia, and she was stressing out big time. She mentioned to me that she heard that smoking helps to deal with stress, and did the same thing, pledging to quit smoking once her husband came home. Which she didn't do. Unlike the first one, I wasn't exactly on her husband's Christmas card list afterwards. He went to the Gulf, leaving behind a wife who didn't smoke, and came home to a smoker. As mentioned in the other thread, I was a partial influence on my daughter starting, but I give most of the credit there to her school friends.
A third that I think of, not one that I influenced to start smoking, but one, as an ex-smoker that I influenced to start again, was my late husband. When we started dating, he promised he wouldn't get on me about my smoking. After we had been dating for several weeks, during dinnner out, he mentioned it would be easier to stay quit if I too quit. I sighed, said to myself "oh shit, I see where this relationship is going, it happens every time I try to date a non-smoker". I got a bit defensive, and said, "well, we both know that's not going to happen, and you promised me you woundn't nag me about my smoking". It got quiet for a bit, and I tried to make a joke, "it would certainly solve problems for both of us if you started again, you obviously miss it". Well, during the course of the evening, he bummed a few of my cigarettes. The next weekend, when we got together again, he had his own.