Julie, a friend of mine, came up with a perfect description of the process.
She said that when you first write a story it’s like a baby: perfect and precious in your eyes.
After a few redrafts it grows into a young child: you see that it has its faults, but you love it anyway.
But as you keep rereading and improving, a story becomes a teenager, lurking in its bedroom and complaining that you don’t understand it anymore. Catch it on a bad day and all you can see is its faults- everything about it irritates you. If you’re honest with yourself, you realise that you’ve both been in each others company too long: you’ve both changed.
By that time you’re looking forward to the day when your story can go out into the world and start earning a living. That’s when you can both see the best in one another again.