The author didn't have to say it, you should just get it.
May Need A Better Name, Needs More Examples Bob asks Alice why is afraid of dogs. She tells Bob there is no particular reason why, but as she scratches her ankle, the audience can see a rather nasty bite mark on her leg, out of Bob's view. It is never discussed again thoroughly. Often, characters will have a Freudian Excuse for a behavior they have. But the writer doesn't need to tell you exactly what that Excuse was. Sometimes, little pieces of dialogue or certain actions toward things can give hints as to what exactly happened to them. The range of hints can range from The Blatantly Obvious to Viewers Are Geniuses. This may be a case of People Sit on Chairs