To make software user-friendly, we added progress meters whenever the computer performed a lengthy task. Often, this was more work than you might think. It’s usually easier to just start doing the work and notice when the work has run out than to calculate how much work there is to do so that you can report the “percent done” as you go.
Sometimes, though, we’d run into something where we really didn’t have any way to know how much work there was to do. So, we’d use some type of spinner or throbber. The user didn’t have any idea as to how long the operation would take or how far along it was, but at least they could see that progress was being made and if progress stopped.
Then we’d get lazy. Even when we could calculate how much work there was to do, we’d not bother and just throw up a spinner instead of a progress meter.
Then came the lie. The spinner became an animation that continued whether progress was being made or not.