Delete a directory, crash the system

[David Noel]

I had a strange experience on my laptop yesterday. I was deleting a
directory and the system crashed. It spat out a message along the
lines of "ufs_dirrem bad link count 2 on parent". I thought it was so
strange I repeated the process several times, and each time it
crashed. Is this behavior EXPECTED? I can't for the life of me think
of a time or operating system I've run where I've ever had a system
crash on me from doing something as basic as deleting a file. Anyway I
couldn't boot into single user for some reason so I booted from a USB
image, ran fsck, and then everything was fine.