For me it would be something more along the lines of I need to write it down (quickly) before it gets washed away by the waves of other things in there. That is only partially true, and doesn't explain my messy writing the rest of the time, even when trying to write neatly (and consistently, which is another problem when I write). I never "mastered" cursive/script, and it is so bad that even I can't read it most of the time, so I don't use it often. A more likely excuse is that I never bothered to spend the time and effort to get better at it, since it seemed wasteful, and I focused on other things instead of a new way to do something I already knew how to do.
On a somewhat unrelated note, I was trying to encourage someone that was embarrassed or ashamed at their performance when trying to apply new skills they learned, and making a mistake (...kinda, they were supposed to pretend to do something with the system they were working with, and they did it for real, mostly the correct way as far as I can tell). What I told them works for most people in many situations: don't be afraid to push the limits and make mistakes. That is how you learn and get better at things. It is nice to learn from other people's mistakes and experience, but that isn't always a luxury we have, and it is often valuable to go off the beaten path and find new things for yourself. This is also how we learned as children.
My advice to everyone reading this is to get out there and do something stupid today, and value what that experience teaches you.