For reference:
if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it
if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it
For reference: it's called Kernighan's Law, and can be found in the Second Edition of "The Elements of Programming Style", page 10 [1].
The original phrasing is:
> 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?
[1] https://archive.org/details/the-elements-of-programming-styl...