An old man walks across a lake that shimmers in the light, while the sun, far off, seems to spin loose from the horizon like a hubcap rolling away from a wreck. It's a strange, slightly violent image for a sunset, and it makes the end of the day feel like an accident rather than something peaceful. The wind roughens his face, and the speaker wonders whether the marks come from sand or from age.
Then the poem shifts to a theater. The other "bit-part actors" slip away one by one, the audience coughs and files out, and the lights snap on. What's left is the old man, still performing his "scripted pathos" to an empty house. The speaker seems to see his sadness as something rehearsed, perhaps even a little theatrical, and yet also painfully lonely. The mood is quiet, bleak, and faintly ironic: a life winding down with no one left watching.