However, sometimes you can design a system so that people are less frustrated in the first place, and have what they need to resolve problems when they come up.

The trouble with a linear storyline is that one must of necessity leave things that do not impinge on the progression of the story out.

Of course there's a sign with a phone number to call in case there's a malfunction, right there on the face of the machine.

However, I had no interest in educating the boy, who was clearly already angry or having 'way too much fun; my goal was to get him away from the machine and out into the day where he could cool off and perhaps find a friend who would have pity on him and buy him a bag of corn chips.