I remember the time i was learning linux. I used Manjaro at the time (I know I shouldn't have) and once I pacman -Rcnsed a package. Well, my entire kde suite was gone. Had to look through pacman logs and manually reinstall kde.

Another time I was trying out netboot.xyz (I dont remember which distro). I went out for a moment and by the time i came back the distro had formatted my drive and installed itself.