I remember doing something similar except it was with my cable provider, when they first came into town.

Since all clients would basically be connected to a LAN, as soon as I found I could port scan random users I started doing it.

Of course there were a lot of businesses on the network that apparently used FTP to move files around but were unsecured.

I spent the better part of a couple of weeks just going through the data (never actually downloaded anything since I knew it could land me in trouble with my parents).

Like you said, I also cherish this story since it was a rare peak at other peoples lives... without even knowing a 12 year old had access to all their business files.