Singing to yourself

The other day, I walked right up main street singing to myself. That isn't an unusual thing. For me I mean.

But it hit me that a lot of the singing we do is useless for actually developing our voices. For I sang quietly as I always do when singing to myself. I didn't want anyone to hear me.

Real singing shouldn't be like that. For starters, how are we going to learn to sing on key if we can't even hear ourselves? And what is the point of singing if no one can hear us?