Whistling

I was just thinking, when was the last time you saw someone walking down the street whistling a popular tune? I mean, in the days when every song actually had a strong melody, whistling was pretty common. I'm not talking about the occasional skilled whistler you come across, a musician, or just someone who has always whistled and is good at it. But just someone in a good mood who caught a tune on the radio and it naturally comes whistling out without a thought. When I worked in a factory as a teenager, there was a guy who would clock in and you could hear him whistling complex classical music as he walked back into the maze of machines. I always wondered what his story was.