The speaker rejects the comfortable idea that there will always be more time. "Time enough" is called a cheat, a phrase we use to excuse putting things off, and the speaker adds that we "make good sport / of losing," as if we play a game we're already doomed to lose. Instead of reassurance, the speaker asks for "the passing of things."
The examples are small and human: a heart breaking during an opera, and a love that ends "after a little sin." Both are painful, yet the speaker wants them. The title, "Ukiyo," is a Japanese word often linked to the idea of a fleeting, changeable world, and that fits the poem's attitude. Beauty and feeling seem to matter because they end.
The mood is wry, quiet, and a little defiant. There's sadness in it, but also appetite. The speaker doesn't mourn loss so much as accept it, and even seems to savor it.