the problem of outines

The question of whether or not to do outlines always plagues me. I always think I should, that there would be so much less muddling around if I knew what I was doing, where my characters were going. But here's the thing. I just spent the last hour writing a scene in which my main character offers something to help another character in trouble, and that character refuses it. I didn't plan that. I didn't know it was going to happen. But it makes so much sense in the story, because the boy in trouble is actually trying to protect someone else by refusing the gift, and by doing so he deepens the story enormously. I love this new twist. It makes everything that comes after it more meaningful because of this added layer. But I would not have been able to include this element if I'd been working to an outline. That's not to say I don't know where the story is going...loosely... just not precisely. And really, that's part of the joy of discovery isn't it?