https://www.youtube.com/watch?v=mcsbDDyfLLU
It turns out that when you either:
1) flick very quickly at a target that is nearby,
or
2) flick slowly at a target that is far away,
then 1000hz is inadequate.
Here's some higher quality stills:


In case you were curious, the way you get 8000hz polling is by using this driver: https://www.overclock.net/forum/375-mic ... 00-hz.html
To get 8000hz polling requires either a mouse with MLT04 sensor (which is quite old, and bad except for its 8khz polling support - it maxes out at 1.5m/s) or a mouse with firmware specifically designed to allow 8000hz polling (currently just the Zaunkoenig M1K.)
Here is a fun fact: it's actually possible for USB devices to poll at 8000hz without any additional work, but the input device has to be something called a "USB High Speed" device which apparently requires an expensive 4+ layer PCB design (hence why no peripherals company bothers.) Why you can achieve 8khz polling on a normal PCB with this driver is beyond me, but there you go.