I'm grateful for editing. Nothing I write is carved into stone. It can be deleted, changed, pummelled into submission or reworked into all perpetuity.
Creation starts somewhere inside you - for the sake of argument, let's call it inside your head. There, your novel, your painting, your composition (any form of art: from a knitted sock to a rocket to Mars) is perfect. It's a thing of beauty.
But when you try to recreate it by writing it, painting it or designing it, it's a lump of hideous, formless, colourless clay. Occasionally you'll get lucky (when the gods are smiling on you or you've had a seriously large shot of caffeine) and the recreation works. Mostly, it's garbage.
This is what editing is all about: you now have to take your formless lump of clay and work it. You have to pummel it, chop bits out, add bits, go over it again and again. You have to shape it and reshape it. You have to sweat over it. You have to research bits of it. You have to rethink other bits. You can even get someone else to inspect it and get their opinion, but, ultimately, the recreation is yours.
In the end, you're never going to recreate that perfect thing you created inside your head. But you can get close. And it takes work to get close. With experience, you get better at it. With time, your first lump of clay requires less work, less sweat, less tears.
Editing isn't about fixing up mistakes. Editing equals Art.