MMario, I must take issue with your statement.

You're in show business (even if you don't get paid) if your performance has something to do with charging money for goods and/or services in the hope of making a profit. When I invite friends to my home for any purpose, no money changes hands and I am not seeking a profit of any kind. Therefore, their performances -- however polished and complex -- are not show business.

However, if I play my mandolin in a session at a pub, I'm engaged in show business because the owners of the pub permit the session to take place only because it attracts punters who either enjoy diddly music for itself, or like to bask in the quaintness of impromptu diddly music while they drink their beer.

If the same session moves to non-commercial space in the community centre around the corner, its show business element disappears. (Of course, so do most of the better players, who come not only for the experience of group playing but also for the thrill one gets from playing for an audience.)

So my answer to the original question is -- Sometimes.