The serendipity argument is real, but I think it's about the ratio. If one scroll in ten turns up the container ship video, great. For me it was more like one in two hundred, and the other hundred and ninety-nine made me feel worse.

That's fair, and I'll admit I've trained mine hard. I hit 'not interested' on anything with an angry face in the thumbnail, and it took weeks. Most people never do that, and I'm not sure they should have to.