I got two thoughtful responses to my previous post, which will provide material for more than one post in the near future. Thank you to both who responded!
I was thinking about this after posting earlier: what about feedback that isn't wonderful?
What if, for example, one gets feedback from a professor that says something like "What a fool you are! I'm writing to the department to ask for your dismissal"? Or something less drastic like "This is great! You're making progress and at this rate you might finish in a few years after you do some more research"?
There's no easy answer for this one. The plain truth is that feedback can be difficult. But like any problem that arises, any difficulty, we will respond in some way. The question that remains is how we respond. One possible course of action is to consider what to next; to focus our energy on how to proceed from that moment on.
There's a lot more to this issue, but I don't want to get caught up in it right now.