Everyone knows that debugging is twice as hard as writing a program in the first place. So if you're as clever as you can be when you write it, how will you ever debug it?

Brian Kernighan - The Elements of Programming Style, 2nd edition, chapter 2

A similar phenomenon is knowing you're going to need to go back and update some older section of code and when you finally get around to it, it turns out you wrote it that way to begin with. It's like... I didn't think I knew about this approach before...

"I'm dumber but wiser" - me, hopefully

This right here. Plus stuff like "this is the functions section" and "this is the main script" helps make shell scripts more readable because functions have to come first, and if you just want to get to the main point, you can skip the functions section.