The quote from James Joyce's "Ulysses" serves as a cautionary reminder about the dangers that may be present in seemingly blissful situations or appearances. The horns of a bull symbolize physical strength and potential aggression, while the heels of a horse represent speed and unpredictability. Together, they suggest that one should be wary of powerful forces that might bring harm.

Furthermore, the reference to the smile of an Englishman adds a layer of complexity, hinting at hidden intentions behind charming exteriors. This implies that outward appearances can be misleading, and one must remain vigilant against those who may bear a friendly demeanor while hiding their true motives. Ultimately, the quote emphasizes the need for discernment in assessing both people and circumstances.