The first 5–30 seconds decide the video: the open must confirm the title/thumbnail promise then exceed it. Hooks must work on mute. Hook length is ecosystem-specific (15–45s long-form, 3–8s shorts).
Taught by Jon Youshaei
that 15% difference in viewership really does make the difference between hypothetically like 2 million views on a video and like 10 [million]