This poem has a very depressing message and it is mainly about death as many of Larkin's poems are. The rhyming pattern is repeated in all of the stanzas which could suggest that death is inevitable also the fact that the rhythm is a heart beat, again highlighting the inevitability of death. sometimes there are half rhymes which are less satisfying than full rhymes, maybe suggesting that life is not overly satisfying. Larkin says 'That lies just under all we do' maybe he is talking about death and this is suggesting that death could come at any time and it could happen to anyone. At the end of the poem we expect the last word to be die as it rhymes with 'by' but instead we get the word 'are' this could be Larkin's way of saying that death is not the end and that there is life beyond death. This is not a view that we would typically expect from Larkin.