What you learn from doing a PhD

This is one of the best explanations that I've seen on the process of getting a PhD:
To survive this period, you have to be willing to fail from the moment you wake to the moment your head hits the pillow. You must be willing to fail for days on end, for months on end and maybe even for years on end. The skill you accrete during this trauma is the ability to imagine plausible solutions, and to estimate the likelihood that an approach will work.

If you persevere to the end of this phase, your mind will intuit solutions to problems in ways that it didn't and couldn't before. You won't know how your mind does this. (I don't know how mine does it.) It just will.