Bonta's poem is four lines long, and it moves from irritation to a small, odd comfort. It opens with a sharp image: the day is "like a nettle," prickly and hard to touch without being stung. Then the speaker names the problem plainly. It's a day for stress, which he calls a "private, ordinary infirmity," something everyone has but nobody sees.
The third line is stranger. "The sight of her ear will do me" suggests that just looking at someone's ear, presumably a person he loves or is drawn to, is enough to get him through. It's a tiny, tender detail, and the poem doesn't explain it. Then comes the surprise ending: he spends the afternoon eating lobster.
The mood is dry, wry, and quietly affectionate. The speaker doesn't fight the bad day. He answers it with small pleasures: a glimpse of someone close, and a treat. The humor comes from how casually the luxury is dropped in after all that prickliness.