Getting really speculative, but maybe Infinite Scrolling and similar UX design patterns. I think we learned it was dangerous pretty early in, but I have a feeling there isn’t currently a widespread understanding of just how badly things like infinite scrolling shortcircuit parts of the brain and cause issues with attention and time regulation in large populations.

If I was more researched on it, I might include infinite short-form content feeds of almost any type to be honest, which may just be another way of saying social media.