Imagine reading a book or a story or watching something, that ends with these words, it will be the most frustrating thing ever. Imagine this happening in a story about mystery. (the anger!)
What usually happens when this line comes is that the viewer or reader is left wondering about the story. This makes the person think so much about the possible ending that he or she exhausts all their ideas.
Be it the last episode of a season from House Of Cards, Flash, Sherlock Holmes or Homeland. All these have given us the suffering of waiting.
Even though not explicitly stated, they do end on such terms. Such semi endings also builds up a lot of tension and curiosity. More the curiosity, more the views the next episode will get.
So, this can also be called a marketing technique of sorts. And so, it is safe to assume to this is obviously a nightmare for the reader and viewer, no matter what the reason is.
