Yujeong did not want to get her coffee by herself at the first place, but she did not regret it at the end.  

As a mermaid, it's natural that all Yujeong wants to do is stay under the sea where it's safe and away from the unknowns of the forbidden surface world. Solbin, however, lets curiosity get the best of her and ends up taking Yujeong above to break all the rules they've lived by.

Solbin is definitely no social butterfly, but her friends somehow manage to convince her to sign up for Camp Laboum for the Performing Arts. She doesn't expect to gain much out of the experience - that is, until she becomes acquainted with the likes of Counselor Yujeong, who demonstrates exactly how wonderful (and attractive) people can be. She can't say that she regrets spending her summer at Laboum, not when she's found the remedy for her painful introversion...and possibly something more.

Whenever Hyejeong needs someone, Yuna will always be there. Yuna is always the first one to be there for her. Did she take Yuna for granted? Or she just love Yuna and just rely on her unnie so much?