A piece of writing is only a failure if it goes unfinished. At all costs, you must bust through that finish line ribbon. But it's hard to finish a project and write "the end." It's easier to keep revising forever and ever. And that's because we know that once a piece of art is finished, it ceases to be ours. Now it belongs to the universe. The child is independent of the parent.
10 yards from the finish is when all the insecurities come on stronger than ever before. The fears have been barking all along, but now they're snarling and spitting in your face. They want you to keep that piece of art "in progress", away from any potential rejection or failure or negative feedback.
But the road from amateur to expert involves practice, failure, and experimentation. As an artist you aren't allowed to skip spaces on the game board. There are no shortcuts, no freebies, no "advance to go" cards. You can only get better by progressing slowly through each stage.
And that's why unfinished works don't help us. They don't move us forward. While a finished piece, even if it isn't a masterpiece, is always a lesson learned and another brick added to the foundation.
Nearly every successful writer says, "My first three novels are still sitting in a drawer somewhere. Nobody has ever read them." I hear it all the time on author interviews. Those first few novels were garbage, so why did they even bother? Because those lackluster stories were the critical bottom rungs of the ladder.
So write your crappy songs. Paint your ugly pictures. Tell your scatter-brained stories. And in doing so you'll slowly build a ladder to the sky.