Reading this thread has been incredibly insightful for me, and I hope everyone reading this thread can take as much from this thread as I have.
Firstly, No one playing loads of Dominion is ever infallible. The more games a player plays, the more likely she is to not make mistakes. However, there will always be that chance of a mistake, and as she plays tougher and tougher opponents, the choices and actions taken become more and more subtle but just as (if not more) important to make and do correctly. I think everyone needs to realize that they can be wrong, and be open to correction. There's nothing wrong with being incorrect sometimes, or even all the time.
Secondly, and what naturally follows from the first insight, is that gleaning knowledge of the game never stops. As a direct result, I must take all criticism with utmost sincerity, and bring it into my next game where it is relevant. An example of this is the list of priorities, where I had always thought of 'Doing A, B...', and then 'Y' follows. My mind has been opened, much as it has been multiple times as I have played Dominion, and now I will think more about the natural flow of the game, and not as much about logical lists. Another example would be the concept of cycling discussed by Rubby.
Thirdly, again flowing directly from the second point, there is such an important element of Dominion that I have found that is vastly unappreciated. This element is the ability to take the game, and how you think about it having direct effects on your play. If Player Donald thinks Dominion is a game of luck, that's how Donald will approach the game when you win and lose. Following this train of thought, if you 'hate' a certain strategy, you'll be more apt to ignore it, even if it is the best play.