The menorah was fashioned from one solid block of gold. Nothing was grafted on to it. Just as its base, its shaft and its cups were integral, drawn from the same block of gold, so too were its knobs and its blossoms integral and drawn from the same block of gold. The same is true with every law that the Rabbis promulgated. Nothing is grafted on.
Nothing is unrelated embellishment.
The lily is ungilded. He just didn't fit. His father was worried sick that his estrangement from Torah study would precipitate his fall into the wrong crowd. His son sensed his father's anxiety. On the surface, this is a non-sequitur.