picture shows a paper towel dispenser in a restroom.
The problem is that to get a paper towel
to dry your hands, you have to reach into a pile of
used towels! The little container that holds the
used towels is too small and
is just a few inches below the slot where the clean
towels come out.
kind of problem could have been easily avoided by
just putting a prototype dispenser in a restroom
and checking it occasionally.