Spoilers: making people angry since Victorian times

It’s fair to say that with the release of the latest series of HBO’s Game of Thrones and another instalment from Marvel’s Cinematic Universe, Avengers: Endgame, the “spoiler” has never had so much power. Twitter and Facebook have become no-go areas for those yet to watch them, while various guides are offering help on how to live “spoiler-free” online.
In the “real world”, someone’s attempts to leak the conclusion to Endgame outside a Hong Kong cinema reportedly led to them being attacked.