Linchpin

The piece of the jigsaw puzzle that approaches the level of a linchpin in terms of being the key to locking impressiveness into the proceedings and completing the picture when it's there (photo) isn't the largest or most obvious piece located in the center or even around the center.
It's a relatively small piece located in an almost forgotten place, off to the side near a corner.
It's the music ... provided by the musician(s).
This little puzzle piece, comparatively speaking, seems superfluous to many when it's there, and it's contribution seems minimal ... people understand that the whole puzzle will still hold together without it.
And that's all well and good.
But take it away and see what happens.
It leaves a heck of a hole.
If you can play the organ at all, you're willing, and your health allows you to be able, people can't help but notice if you, your equipment, and your talent, all three, are present.