Those Dyson hand dryers (and the numerous knock offs), where you have to stick your wet hands between two sides of a dryer and dip your hands up and down to dry them.
They're expensive, so minimal numbers are put in public toilets, they cut out unless your hands are 'just so' between the sides and the water simply dribbles to the bottom and then down the walls.
Many women seem to just pull out reams of toilet paper instead and, because these dryers are supposed to cut down on cloakroom waste, find there are no bins. So they leave manky balls of toilet paper all over the sinks.