Progress (in Pottery)

I made the hand-washing cup on the right about a year ago, and I brought home the one on the left just yesterday.
The older one has a kind of childish charm to it, but it's heavy, the handles are clumsy, and the drawing on it is crude.
The recent one is a lot bigger and more gracefully shaped. I wasn't able to make large pots at the time that I made the first one. The glaze came out pretty well, the handles are neater, and, while I expect that in a few years, if I keep doing pottery, I'll see it as crude and clumsy, the flaws in it are more apparent to a potter than to an ordinary person.
I imagine I'll reach an age when all my systems will be in decline, but, fortunately, I'm not there yet. I'm still engaged in things that I can get better at.
For now, I'm less concerned with the things that I make in my weekly pottery class than with gaining skill and mastery. I'd like to make large pots, but, though I'm improving, I still can't keep the clay centered well enough to do it consistently. For the sake of discipline, I spent the last five or six sessions making nothing but mugs. Some of them came out decently, but I still am not able to produce a form that I have in mind in advance, and to produce the same form consistently, time after time.
I could rationalize (and I do), saying that it's more creative and spontaneous to work the way I do, but higher creativity comes from mastery of technique, and higher spontaneity comes from the ability to do what you set out to do.
Still (here's the rationalization): I know, from writing and music, as well as from pottery, that the best moments are the ones when you surprise yourself, when you write something you hadn't thought of before, when you play a solo that is better than you thought you could play, and when you see and feel something in the clay that you didn't know was there.
By the way, for anyone who might read this and isn't familiar with Jewish ritual, the hand-washing cups are used before meals, with a blessing for washing hands, before one recites the blessing over bread.