If we could so readily write this stuff down so that we can come back to it, we could have already banged it in through the keyboard and be done.

What's going on in a good programmer's head is going to be complex and detailed, because we need to understand it to be able to write it, and that basically means we're running the code in our heads before we commit it to a screen.

We're not "setting [ourselves] up for failure". We're solving hard problems with the expectation that we won't have to come back to it in an hour's time just to erase all our poorly planned code and start over. It's not like writing an email--we're switching modes over to thinking like a computer and this requires concentration and focus.