I'm 54 and one of my friends happens to be half my age at 27. She and I met ten years ago when she was 17 and I was 44 when we both did volunteer work at a local retirement/nursing home. We usually worked together once or twice a week, schedule permitting, for three years, before life took us in different directions. We enjoyed each other's company and she would needle me about how old and out of touch I was, and I would reciprocate, telling her stories about what things were like when I was growing up and her age. There was never anything remotely sexual about it, I just thought of her as another niece who is the same age as my real niece. We're still friends on Facebook and we exchange Christmas and Birthday greetings every year.