Eh, things happen ;)
I personally am no longer fond of layers, for the simple reason that they separate the image too much and make it look broken down even if flattened. The colors often do not match up, the shading appears divided, etc. It\'s a lot like taking the traditional media approach - step by step on the same canvas. If you mess up, try to cover it up and do all the steps over again. The image looks more \'together\' that way, but it could just be me :)