Under its Latin title, "seize the day," this tiny poem makes a blunt argument: everything is calling to us, and everything is also falling apart. Decay is built into the world, so why hold back? The speaker's tone is half-apologetic, half-impatient. "Excuse my not / waiting as others do" sounds polite on the surface, but it carries a quiet shrug at the people who stand by, expecting life to start later.
The last line, "to be," is the clever part. It hangs alone after a line break, so the sentence seems to stop short. Read one way, others are waiting to exist, to really live. Read another way, the speaker simply refuses to put off being alive. The short lines make the poem feel hurried, as if lingering over it would defeat its point.
The mood is brisk, wry, and a little sobering. Rot and falling are mentioned plainly, without panic, and that calm gives the urgency its force.