So I was walking down the the grocery store to pick up a couple of things for dinner at around 7:15 tonight so it was still rather light outside. I had Whittemore (my fs m&p 9mm) IWB strong side and was trying my best to be situationally aware. I noticed that at one point a male about my age in basketball shorts and a t-shirt started walking behind me a ways back, I turned my head to look, making sure he knew I knew he was there. I noticed that he was walking a bit faster than I was so I really paid attention to how close he was, turning my head often. I gave him wide berth when he was getting closer and when he was about two or three feet behind me I turned and he said "Hi" I replied "Hello" once he was slightly ahead of me when he turned to ask if I had a cigarette, since I don't smoke I firmly, but politely said "No". He continued on walking and went into the same grocery store I was going to. I kept an eye out for him while shopping and on my walk home. I did not see him again. Got home and cooked up my surf and turf dinner. Any thoughts on my actions? What should I have done differently?