Why do white men try to get ethnic people's presence?

He was just a friendly person. Many whites find ethnic people to be exotic. Similar thing happened to me when I lived in London except all he said was "wow you're so beautiful", but the man actually invaded my space and reached out and touched my face while he was saying it! This was at a supermarket there and the white man appeared to be in his late 40's. But I remained polite and thanked the man before walking off.