Why we watch almost everything sped up

At first you switch it on for a specific reason: a lesson to revise the night before, a video that rambles, someone who really does speak very slowly. Then fast becomes the default setting, and it's normal speed that feels odd - too slack, almost irritating. Nothing was ever decided: the ear simply got used to it, and the habit took the place of the choice.

What we're really speeding up is the queue

The list of things to watch always grows faster than the time available: videos set aside, the series everyone is talking about, recorded lessons stacking up. Speeding up gives a very concrete sense of getting back on top of that pile. But what you gain on is the queue, not the video itself: you don't watch better, you watch faster so you can move to the next one. Hence that strange feeling of having seen everything and remembering almost none of it.

Silences are not dead time

A joke rests on a pause before the punchline; a moving scene hangs on a look held a beat too long; a hard explanation deliberately leaves a few seconds for the idea to settle. Fast speed shaves all of that off at once, without telling filler from meaning. The test is easy to run yourself: take a passage you found flat when sped up, listen again at normal speed, and see whether the passage was really the flat part.

Choosing your speed, rather than being stuck with it

There's nothing wrong with speeding up: for revision you already know, for a tutorial where you're hunting one passage, it's actually the right answer. The useful reflex is to match the speed to the material - fast for what you're skimming, normal for what you want to understand or for what you chose to enjoy. And when a film you'd been looking forward to also ends up on fast speed, the real question is no longer the setting: it's whether you wanted to watch it, or only to have watched it.