"I need to know what happens"

The cliff is the part you'd defend. The detective opened the door. Something was behind it. You can't sleep on that.

Consider when the wanting arrived. Not at half past nine. At quarter past ten, in the last two minutes of the episode, when the writers put the door there. The episode was constructed so that its final scene would produce, in you, a need to see the next scene, and the need was produced on schedule, and you experienced it as your own. It isn't yours in any interesting sense. It was made for you, at minute forty-four, by people whose job is to make it, and it would have been made in anyone sitting where you were.

Now consider when it's resolved. The next one starts, and within two minutes you know what was behind the door, and the need is gone, and you're watching an episode you hadn't planned to watch with the reason for watching it already spent. For the next forty-two minutes there's no cliff. There's a story, which is fine, and then at minute forty-four there's another door. The wanting is built, resolved and rebuilt on a cycle, and the cycle is the length of an episode, and the countdown sits exactly where the wanting peaks.

This is my reading of how episodes are made and not a finding from a study, but I don't think anyone who writes them would dispute it. The cliff is the mechanism by which a show that's designed to be watched in sequence gets watched in sequence, and it works on everyone, and it's supposed to.

Here's the thing about needing to know. It's true tonight and it'll be true tomorrow. The door will still be there at half past nine tomorrow, and what's behind it will be the same, and the two minutes that resolve it will be exactly as satisfying then as now. Nothing about the answer decays overnight. What does change is that tomorrow's version comes at the start of your evening, when you've got the time for it, rather than at the end, when you've got the alarm. Chapter 21 has a test for this, and it's simple. If you need to know, you can know tomorrow. The need survives the night. The sleep doesn't.