The process of mastering something is endless. There is always another level of understanding. With pottery, the first several layers deal with technical skills. It takes countless hours at the wheel to get anything that is well made. And then there is beauty. Why does that one mug grab my attention more than the others on the shelf? Even though we work toward perfection, I think the actual answer to this question is that a pot is best when it is perfectly imperfect.
I often think of the Muslim practice to deliberately create a flaw in their prayer rugs to avoid becoming too proud. But, what if they didn't? Besides ensuring humility, I think it adds interest and dimension to the rug. That touch of asymmetry, that one place that subtly catches the eye draws you in. I think it makes the rug more beautiful.
A machine can make incredibly precise pieces. A tea cup made in a factory is exactly round, impeccably glazed, and without a single blemish. But it is missing something. The mark of the human's hand. I think as we strive for perfection in our work, it is possible to also miss the point. The energy and attention that goes into a hand-made item gives it a richness that is unique.
I am reminded of this on hand-made items I have purchased that have read something along these lines; "It is precisely the inconsistencies in the hand-woven yarn that gives this product it's unique character." Yes, it is.
I have been spending most of my time in the studio these past two weeks glazing my pots. I've felt more like a painter than a potter. But paints and glazes are very different. Paints, first of all, are up front about their color, while most stains and glazes are far from being "WYSIWYG", or "what you see is what you get." Also, brushing onto clay is difficult because it is rough and textured from throw lines made on the wheel. Also, the thrown pots are round and not flat like a canvas which can warp your intentions. It takes practice and patience to glaze a pot satisfactorily. 
I have been experimenting with combining my stains and seeing how they contrast with each other and the glazes I have. The walnut against the mulberry, the clear against the black; it is like Christmas every time I go down to open up the kiln. And sometimes it is more like the year my parents were especially low on funds - a big let down. The twilight blue glaze is hit or miss. I've tried to combine it with a cobalt glaze I have, and it ended up dripping all over the shelf. I've had glazes cover and hide the stains underneath.
I am working on fixing these problems by taking notes of what I have done on each piece. Depending on how I apply the glaze, (I can brush it on or dip them), how many coats, and its consistency, I end up with quite a range of results. This is tedious work but has proven to be worthwhile. I have been able to fine tune some of my techniques and am happier with the latest pots.