The significant problems we face can never be resolved at the level of thinking that created them.-- Albert Einstein
Another way of saying this might be:
Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it.
Anyway, consider this:
You may speak eloquently on the nature of fire,
but your mouth will not become hot.
You may expound on the qualities of water, but your mouth will not become wet.
As soon as you think you have found The Way, you have stuck your head in a bowl of glue.-- Takuan Soho
Again, another way of saying this might be:
It is better to remain silent and be thought a fool than to open one's mouth and remove all doubt.-- Abraham Lincoln