A writer's work is never done

My oh-so-perceptive writing group was right on target with the first chapter I brought for them to read last week. I probably should have waited until I was finished my draft before showing it to them. And here's why: they reminded me of how much there is to do.
It's not that they were super critical or unfair or even unbalanced. It's just that they were right. And, looking at the flaws in the first chapter, I could see how I've carried some of those faults right through the entire manuscript. We're talking serious voice issues here. It's not easy to pretend to be a fifteen-year-old boy, folks. Especially a sarcastic, funny, crass, hormonal boy with attitude.
Except for the funny part. I can do that. I'm HILARIOUS. Have you ever read my blog?
They didn't dwell so much on my other serious issue--plot. For some reason, when you write a novel, you're supposed to have stuff happen. And it's supposed to make sense. When I write, I just fly. I don't plan ahead and I don't edit until after I'm done. In some ways, that's good because it allows my thoughts to come through uninhibited. In other ways, it's a pain because my plot (and my subplots) wander all over the place. I don't focus enough on the stuff that matters, and I get too wrapped up in secondary characters.
Now it's that much harder to write, knowing I have so much to fix. Imagine you plant a field. Then a professional farmer comes along and tells you some of the rows are in the right place, but now that you've got everything planted, you've got to pull up about 3/4 of the plants, re-sod a quarter of your field, and then double the size of your field somewhere else. It's enough to make me not even want to finish planting the field.