What's the hardest page you've ever tried to screenshot?

I build a full page screenshot extension, so I've spent an unreasonable amount

of time on this, and I'm curious what breaks it for other people.

The ones that caused me the most trouble:

Sticky headers. They stay pinned while you scroll, so a naive capture puts the

same navbar down the image forty times.

Lazy-loaded images. Scroll past too fast and you photograph grey placeholder

boxes instead of the picture.

Infinite feeds. The page grows underneath you, so any height you calculated at

the start is wrong by the time you get there.

Seams. If your scroll position is off by two pixels the strips don't line up,

and your eye is very good at spotting a repeated row of pixels through a line

of text.

What's yours? Genuinely interested in pages that defeat the tools, partly

because I'll go and test them.