I had something like this happen not long ago. I was walking down the street and a man pulled up along side me and looked expectant. I had headphones in so I didn't hear what he said, but I saw him speaking to me and smiling weirdly. I just stared at him blankly (with my headphones in), until he got uncomfortable and left. I turned down my music to walk home and just felt off for the rest of the day.