800 years or so ago Dogen said something to the effect that no thought requires a second thought (I paraphrase).

In a talk recently Nyogen Roshi said something that really helped me out of a place where I was stuck thinking about things I had screwed up. I mean things going back 50 years in some cases. Quite a litany when you reach into your bag of tricks that far.

He said:

All thoughts are self liberating.