A great quote by Erica!

some wounds are resistant to the restorative agency of time

That's because the restorative medicine called revenge (see all Shakespeare plays and Tarantino movies :D) has been denied them!

I enjoyed the point that it's not just Negative Nancies that don't let go of their past sometimes, but also Positive Paulies.

Something similar to the letter-writing technique was recommended by the author of Unf*ckology in that video: she said she found it useful to think of 'what would X do in this case?', X being a person she admires or wants to be like. I guess it's the equivalent of 'What would Jesus do?' In the letter-writing case, that idealized persona is embodied by our own future version of ourselves.

EDIT: I read some of the comments, and for some reason Eternal Sunshine of the Spotless Mind came to mind when reading all those experiences and exhortations about moving on from our past. I guess that movie is something like a counterargument. Do you think there is something special about the past that we shouldn't let go of? What would your stance be if the technology from the movie became available in the future, and people deleted memories in order to live mentally healthier and less painful lives? (Note that scientists have already succeeded in deleting memories from mice! I googled and found an article that even mentions the movie!) I know your position is that the past is valuable but that we shouldn't cling excessively to it in a navel-gazing way, but still some people would rather run away from the past completely, and I think that could also denote a psychopathology of sorts.