Because the key to understanding depression, imho, is to view it as such: a battle within yourself. A constant battle, and no matter how self-aware you are, how much self-insight you have, very often what you know to be rational doesn't connect with how you feel, how you think. Which means that you constantly need to be on alert, and check yourself, and find a way to beat down what you "know" isn't true, but what you feel so deeply (I'm a failure, I have no future, etc.) with rational counterarguments. But you never know whether it's going to work today or not, so you need to be able to make that informed decision on a day to day basis. And in terms of fic, you cannot do that without a warning.

This. This all over the place. I want to add that it's so very, very hard to fight those feelings of worthlessness/insignificance with logic, because logic has so very little to do with them. But most of the time you're down there, logic is all you've got left to fight it with, inadequate as it may be.

Thank you for having the courage to come and express this so eloquently, clearly, and rationally, anon; thank you for being honest and willing to say it.