Hmnn ... Hum
It can be an annoying habit, but people hum.
What do they hum?
At this time of year, in this country, what people hum are Christmas carols.
The tunes are beautiful --- and pervasive. The commercialization of Christmas surely must have it's downside, but that isn't one of them.
I bet even Orthodox Jews and Orthodox Moslems in America --- find themselves humming Christmas carols.