[lelandfe]

Former frontend performance guy here – "Cumulative Layout Shift" is the measure of this jank, and yes, it is the absolute worst.

Conversely, it's hard to overstate how magical sites become when you get that down to 0. Once stuff stops shifting, users are effectively fooled into believing that sites are finished loading. Sites just feel fast, even if things are still happening. It's sadly hard to get there, and very easily worsens.