I think that anyone that thinks they have it all down is not looking hard enough, not looking deep enough, or not raising the bar. From our point of view, we don’t want to find zero issues. If we’re finding zero issues, our bar is in the wrong place. So we begin to raise the bar to find issues, and we keep doing this. If you’re doing that, you’re always finding something.
Apple CEO Tim Cook, on Apple’s supply chain.