That's also why many programmers have gone the other way and just show "progress indicator" instead of progress bars. Like the spinning wheel on Windows. It just shows that the PC didn't freeze and is still working, but you don't have any indication on how long it's going to take. Also if "time" isn't a parameter itself then the progress bar can never be give you a proper "remaining time". A countdown is always accurate because the time itself is the parameter that makes it work. Filetransfer ist based on the files and not on the time, so it will finish when it is finished, not when a certain amount of seconds have passed (like the queue in the supermarket. Fewer people doesn't mean the line is faster. There are just fewer people in front of you.).