This quote from 'The Wedding Contract' by H.M. Ward adopts a humorous and cheeky take on mermaids, blending fantasy imagery with a playful commentary on anatomy and fashion. At first glance, it might draw a smile or a chuckle due to its witty twist on why mermaids are depicted topless—the idea that their "boobs are too big" and that all bras are "C shells" cleverly plays with the literal and figurative shell concept associated with mermaids.

Upon reflecting deeper, the quote can be seen as both a lighthearted joke and a commentary on the absurdity of standard sizing norms and societal expectations regarding women's bodies and undergarments. By pointing out the metaphorical mismatch between form (the size of the mermaids' anatomy) and function (the standard bra size limited to C shells), it humorously questions the arbitrariness or limitations of these social constructs.

The imagery of mermaids swimming confidently and unfazed might also subtly highlight themes of body positivity and freedom from restrictive norms. Mermaids, as mythical beings, live unbound by human restraints, symbolically perhaps promoting a natural and unapologetic acceptance of oneself. It playfully suggests that even fantastical creatures have their quirks when it comes to conforming to standards, yet they carry on undeterred.

Finally, from a literary point of view, the quote adds character through casual wit, potentially revealing aspects of a character's playful personality or the tone of the narrative. This blend of humor, fantasy, and a pinch of social commentary is effective in engaging readers and evoking relatable amusement. It reminds us how humor is a powerful device in storytelling—from embracing the whimsical to fostering reflection—without ever getting too heavy or overt.

Overall, the quote uses humor to humanize mythical creatures while lightly addressing themes of body image and societal expectations, wrapped in a fun and accessible manner.