A character locks themselves in the bathroom
I didn’t participate in this kind of nonsense when I was a kid, much less as a grown adult. I don’t think I’ve ever been in a situation in which I felt like I had to storm off and lock myself in a bathroom, nor have I ignored the folks standing outside trying to talk me out of it.
This happens all the time on TV, and it’s usually a woman who flees an uncomfortable moment to hole up in the bathroom. She’s usually hysterical and crying, because you know how women can be, and the only logical thing to do is run and hide. No.
This trope serves dual purposes. For one, it’s meant to demonstrate how terribly embarrassing the situation for the person who’s locked herself in the room. You know some stuff got real if you had to flee the immediate vicinity. Two, it’s meant to highlight the relationship with the person who comes to talk them out. Their relationship is obviously special and superior to all the others in their lives if this person can say the magic words to make the door unlock.
Usually, a few other people have tried (and failed) to talk them out, so it’s really a special moment when the door finally clicks and they emerge, feeling better about the world in general. In real life, you could probably pick the lock pretty easily, or have enough interpersonal skills to realize that person probably needs to be left alone, but on TV the bathroom (or whatever room they’re in) is an impenetrable fortress.
Examples: Full House, Three’s Company, and Supernatural