Do I know you from somewhere?
Upon thinking about this, wouldn't it be so wonderful if these people recognized the face of Jesus in me? When Christ indwells us, we should be able to radiate the look of Christ from our countenance. A smile that radiates warmth, a listening ear when they speak, a kind word of appreciation. Everyone responds to these Christ-like acts of behavior. Also, if Christians ask this question of you, the bond of Christ unites and connects individuals with His Spirit. I have felt the Spirit of Christ in strangers and rejoiced when I knew they knew my Lord as well. There's a little Christian praise song that says, "They will know we are Christians by our love, by our love."
Jesus calls us to be salt and light to the world. He doesn't want us to seal that light and salt in tight containers---He wants us to be light in a dark world, and add flavor so that others will want to see and taste the goodness of our God. I pray that when someone asks you, "Do I know you from somewhere?", you can take that as a compliment. You are mirroring the face of Christ in your actions.
May Christ be seen in you today!