Hey!
Since this is very related to a book I recently read and really love (probably one of the best software-engineering related books I read in the last few years, and I do read a lot): 'A Philosophy of Software Design' by John Ousterhout
All the point of that quote/joke really is that it's much harder to write good code which we - as human - will have to maintain than code that just run.
Designing good code really comes down to managing the code complexity. (The more complex is becomes, the more difficult it becomes to maintain, expand, learn, ...)
Complexity is more apparent to readers than writers. If you write a piece of code and it seems simple to you, but other people think it is complex, then it is complex. When you find yourself in situations like this, it's worth probing the other developers to find out why the code seems complex to them; there are probably some interesting lessons to learn from the disconnect between your opinion and theirs. Your job as a developer is not just to create code that you can work with easily, but to create others can also work with easily.
This is taken from the very beginning of the book: 'The Nature of Complexity' (Chapter 2), and all the next chapters drill down in what creates complexity, how to mitigate it, which red flags let you easily identify complex code (i.e. code which a computer will understand without any problem, but which a human will have trouble working with easily), and so on and so forth. Definitely a recommended reading! (I'd like to write a book review about it in the next few days, as soon as I have some spare time)