Programming insights to Storytelling, it's all here.
There is a story about a man who was walking around all day with his donkey. At mid day he was tired and decided to nap under a tree. Only, when he looked in his bag, he had forgotten the rope to tie the donkey to the tree. If he slept, he risked waking up to a missing donkey. A stranger passing-by saw his frustration. "Why don't you pretend to tie the donkey with an invisible rope?" the stranger said. "The donkey will not know the difference." So the man, who was too tired, followed the stranger's advice and fell asleep. To his surprise, when he woke up, the donkey was still there by the tree. He then decided to continue on his journey, but the donkey wouldn't move. Try as he may, the donkey just refused to move. So he went around the tree, untied the invisible rope, and the donkey finally followed.
I was working on a web app recently and I noticed that every time I clicked on a link, I couldn't tell if the next page was loading or not. On desktop browsers it was obvious enough with the browser queue, but not so much on mobile. So I decided to add a loading bar to let the user know.