Drive in general is a phenomenal mess (unless you upgrade and go all-in on team drives).
We inadvertently ended up with a weird heirarchy like A -> B -> C, where A was owned by user 1, B was owned by user 2, and C was owned by user 3, and everything was just shared with everyone else.
Then one day while cleaning up the account of a user who had left, I inadvertently un-shared "myself" (her account) from everything that everyone had shared with her.
This apparently resulted in her Drive account going through everything that had been shared with her and removing it from the directory it was in. In this case, Drive un-shared C to her, removing it from B, then un-shared B from her, removing it from A. Now all of those files still existed, and were still shared to everyone else, but there was no hierarchy to them anymore, at all.
This was a completely massive pain in the ass, meaning that one of our project managers had to recreate the entire directory structure, then go through every document that their knew of, search for it in their Drive, find what folder it was in, and then put it into the right place in the hierarchy.
Thankfully, they were the kind of person who had wanted to go through and reorganize for years, so aside from the sudden and completely unmanagable imposition on their time, they were pretty stoked to have a reason to deal with it. I, on the other hand, learned to just never touch Drive at all and migrate everyone to Team Drives instead.
Which it turns out you can't safely share to users outside of your organization. Fucking great. Thanks, Google.