Happiness here is something the speaker knows well but cannot keep. She compares it to a timid fawn that creeps near for one caress and then darts away, and to dawn wearing a dew-covered crown—lovely, but over as soon as the day fully arrives. Both comparisons make joy feel fragile, wild, and a little outside her control. That “aftermath of tears” hints that joy often follows sadness, yet still doesn’t last.
The speaker’s tone is wistful rather than angry. She has chased these “fawn and dawn” moments for years, and they always disappear into “the brush of another day.” The mood is tender, reflective, and a little lonely: she loves these bright flashes of happiness, but she also knows they will leave her almost as quickly as they come.