Progress bars are subtly evil, they seem simple on the surface but if you want to smoothly animate them you have to know or predict the exact time each segment

Progress bars are subtly evil, they seem simple on the surface but if you want to smoothly animate them you have to know or predict the exact time each segment will take proportionate to every other segment, and in most scenarios this is an exercise in futility, so a lot of progress bars end up being fake. I've seen a lot of cases where progress bars actually jump backwards because these predictions fail, whether it be games or applications, which feels like the universe is making fun of your existence when it happens. Sometimes it feels like a 'this action is not stuck' indicator would be more appropriate.