Clearly from your comment the software is so useful that despite hating it, the users deal with the slowness. Which to me only reinforces they parent's point: c

Clearly from your comment the software is so useful that despite hating it, the users deal with the slowness. Which to me only reinforces they parent's point: correctness and availability is more important than speed. If speed were the most important thing then they wouldn't just hate it, they wouldn't use it.