An intern? Don't pat yourself on the back TOO hard... ;-)

I once sped up an intern's code by just deleting a 30-line function, and doing nothing else. Doofus didn't realize our language had a highly optimized built-in sort, and so he wrote his own inefficient sort (insertion) that overrode the existing one. Poor little guy was so proud of having chosen exactly the right sort, and then implementing it based on his recollection of college... I told him to spend the next few hours just reading the documentation of the core API for our language.