Hi:)
at this moment I would like to say that Polish books have mostly no happy endings. And how is in your countries? As deals Spanish literature I know only "Don Kichote" rather funny though bit too long:(
One of the saddest Polish books is a short story called"Lighthouse watchman". It is a short story written by one of the greatest Polish writers - Henryk Sienkiewicz (he got Nobel prize for Quo vadis). Mostly his books had happy endings thus were so pupular in Poland and abroad but "Lighthouse watchman" is very sad story about a Polish guy who left for US and found there a job as a lighthouse watchman. But instead of taking care of the ships and lighting a lighthouse he was reading "Mr Tadeusz" a masterpiece written by biggest polish poet -Adam Mickiewicz cause he was missing Poland very much:(
As you can expect a diseaster happened - one day he didn't light a lighthouse, a ship broke against rocks and Lighthouse watchman lost his job.
But imagine...he didn't stop reading this stupid Mickiewicz even then! On the contrary - he took "Mr Tadeusz" and went into unknown...
One time on one Polish forum someone asked "help me to write continuation of this story". I wrote one.
Others did the same. Try to guess what happened next.
You have to options - with happy ending and without. I have made drowned this lighthouse watchman in my version:(
LM