psychological price targets
some people decide to cash out when ... etc etc
others get scared when ...
the opposite is also true as a reason to buy in.
When You do this routine long enough you see the same pattern over and over and over, actually I am not surprised from a drop of 1000 in 24h if You look back at the charts you see the same in proportion to the amount ~200 ~400 ~800 so the step 1000 is not strange, next maybe 1200 ?