Those new to Linux hit this quickly.
I can mount the drive, but permissions show the owner as 'Root'. I can not add or delete anything!
They stick a USB Flash Drive or external Hard Drive into their system and the system automagically added the drive for them. Usually popping up the drive in their default file manager. Then they can’t use the drive at all. Thanks auto-mounter! It doesn’t happen always, but frequently enough that one has to wonder why there are still bugs in ~20+ year old software.