I can only say its because this show had our tears running...

The writer knows how to make the audience shed a lot of tears. I appreciate and have huge respect for her. But still, if you consider this show,

The writer is the true Queen of Tears. ( Queen=writer, tears=audience)

Fun Fact: Of the eight dramas which have been produced from scripts written by Park Ji Eun, three of them have "Queen of" in the title.

https://mydramalist.com/people/15977-park-ji-eun

The writer herself mentioned that Tears refers to Baek Hyun Woo as he  cries a lot throughout the sequence of events and is basically the king of tears and Hong Hae In being his wife is the Queen. The title is basically a way to manifest the couple

I don't generally cry during dramas

Because someone was crying in every episode.