Right discrimination is of two kinds analytical and synthetical. The first leads one from the phenomena to the Absolute Brahman, while by the second one knows how the Absolute Brahman appears as the universe.
If he had smiled why would he have smiled? To reflect that each one who enters imagines himself to be the first to enter whereas he is always the last term of a preceding series even if the first term of a succeeding one, each imagining himself to be first, last, only and alone whereas he is neither first nor last nor only nor alone in a series originating in and repeated to infinity.
The fact that we can become accustomed to anything, however disgusting at first, makes it necessary to examine carefully everything we have become accustomed to.