Perfectly sheeting glass can cause problems too, it can kid you into rinsing too fast.
What I have found is that you can be bring the brush down faster than the water is getting away. The safest way is to rinse from the top and let the water run down on it's own.
Next time you do a perfectly sheeting pane, watch it from an angle and you will see that the water continues running for quite some time after you stop the flow, and I mean running Ali the way from the top of the pane.
It's as if the sheet of water is quite thick.
Try this, clean your van screen, mine sheets perfectly. Now try driving for half a mile without using your wipers. You will be surprised.
That film-of water can be thick enough to hide dirt, especially the remains of bird muck.
It's still there when the glass is dry though.