A writer always wants their readers to be saying “and what happens next?!?” TV writers have known about this for decades. It is called the cliff-hanger. A drama series with a cold-opening (i.e. a scene before the opening credits) will have a cliff-hanger of some sort. It will ask questions without giving answers. It invites the viewer to keep watching if only to scratch that itch of not knowing why.
This trick of not telling the audience something can also be used in a different way. The popular website TV Tropes has a term called The Noodle Incident. This originated in the comic strip Calvin and Hobbes and referred to an incident where Calvin got into so much trouble at school he refuses to talk about it. And they had to call the emergency services. Bill Waterson wisely left it unexplained, because in the readers’ minds “it would undoubtedly be more outrageous”, as he put it. The trope is similar: it refers to an incident that is off-stage or off-camera that the characters know about and refer to, but do not explain to the audience. We get to see how characters are defined by their reaction to this piece of unreported backstory.