I had a 1Tb external hard drive on the corner of desk (My fault, i know, but at that time i didn't have a lot of space), i used it to keep mostly unimportant things like game files, VMs, movies and stuff like that. Once i was streaming a movie from the pc to the tv in the other room, suddently the tv disconnected, i went to the pc room to check, and i found out that the evil monster that lived in my house (the cat) dropped it off the desk.
The hard disk died and brought all its files with it, luckly i had backups for most of the important files, but i had to download again around 300GB of stuff.... with my slow internet.