I whistle in public places...... malls, grocery stores paticularly where there's a good echo. When they were younger, my daughters refused to walk near lest anyone think I might be related to them. I've been doing it ever since my Grade 4 teacher admonished me that "A whistling girl and a crowing hen, always lead to some bad end." I even find myself whistling to "MUSAC" Egads! but usually I whistle to any thought that might pop into my head that has a related word. (right now its the BeeGees "its only words but words are all I have.......") I don't know if its an age thing for me, I think its just a form of rebellion left over from years gone by.