Easter egg in dramas

I think most of you already know, but in the media an intentional inside joke, hidden message, or feature called as "Easter egg". I really like when I pick up on an Easter egg. Since I've watched many dramas so far, I hope I'll be able to notice more Easter eggs^^ Here's the list of the dramas I can remember with at least 1 Easter egg. Since I've watched many dramas so far, I hope I'll be able to notice more Easter eggs^^ In You Who Came from the Stars there were the quote May I like you?" by Kim Tan (The Heirs), and Go Hye Mi (Dream High) also took an appearance.