You do this work long enough, and you can usually tell in under a minute if you're dealing with code that takes shortcuts, or a big pile of copypasta from SO.
Thinking that an unambiguous syntax implies it's not creative means something that is creative must have an ambiguous syntax. That's on its face absurd, yet a weirdly common belief.
The question above is mixing dealing with errors and debugging with refactoring and modifying. I think this is the heart of the issue. One can (and should) modify and refactor "good" code too.