A Korean Zen master is fond of wheedling his students with, "Descartes says, I think therefore I am. Now I am not thinking, therefore what?" (Gerald May, Will and Spirit")
My son has a game that is similar to the ice bear game. In the Ice Bear Game someone tells you that for 60 seconds you shouldn't think of an ice bear, but if you do, please count how often you think of it. Of course we cannot help thinking of ice bears once someone puts the idea into our head. This little exercise demonstrates how foolish our hope is that we are in control of our mind.
So in my son's mental game, he says from time to time, "I lost", meaning that he was thinking of the game he wasn't supposed to be thinking of. This begs the question, can we mentally outguess the ego the way Jesus did in the desert when he faced his three temptations, but simply shut the demonic voice up for good by stating "Get thee behind me satan". The only thing that we are responsible for in the end is what we do, not what we think, Jesus and Buddha also couldn't help their temptations popping up. But they had a say in what to to about it, simply nothing.
I would turn the whole thing around. What really matters in the end is the not what we think, perhaps not even about the occasional missed step along the WAY. What matter is the spiritual mission we choose for ourselves and the life choices we make because of it. Learning takes place when we see how life responds to our choices, and by being aware of all the thoughts and feelings that stir up in response. Everything else are just mind games.