Has this ever happened to you?

Not in a pizza parlor and without break dancing or cops but a girl I work with likes to sing while she stacks the merchandise. It's boring and that's how she copes. When I know the song and I feel like it, I join her from the counter and if the boss is around, he will too. From time to time, a few costumers have joined in. It's never too elaborate, certainly not a musical, but yeah, sometimes we sing together at work.