It's an example of the Doorway Effect: brains are wired to work in modes related to context cues. Change the context, and you'll change the memories and trains-of-thought easily accessed.

Polished things have a context of "use", not "evaluate", because we use so many polished things every day, but very rarely have any need to evaluate them (mostly only when we're buying them, or when a repair person asks us to describe what's wrong with them.) Whereas unpolished things are mostly "for" evaluating; it's rare that people use unpolished things (outside of, say, disaster-relief infrastructure.)