I just finished episode 15 and this mysterious guy who is the FL's blind date keeps referring to someone who looked like her that he called Goldfish. She then goes to call him Chef since he is a pasta chef and he says "Na Ri. Hearing you call me "Chef" brings back so many memories...I hope Goldfish is doing well"

I'm just genuinely curious about this...hope someone has the answer 

18 hours later and I somehow ended up finding the answer for this myself while browsing for other serious to add to my plan to watch list...turns out this was a reference to the kdrama Pasta (2010) where Gong Hyo Jin and Lee Sun Kyun (may he Rest In Peace) played the main leads and she was given the name "Goldfish" by Lee Sun Kyun's character during the show. The mysterious person who played Gong Hyo Jin's blind date at the end of episode 15 was in fact Lee Sun Kyun but by voice only, which was why they never showed his face but dropped obvious hints.