Well, I was one of those "armchair" specialists until I got a system why could sustain 60 FPS and I couldn't deny there was a difference between 30 FPS and 60 FPS, even though on the paper 25 FPS "should be enough for everyone".

(from TFA:) > During a rapid eye movement, the flickering light source can paint a streak of ghost images across the retina

So REM could explain it? Maybe it is somehow variable among people?