First, there are more OSes out there besides Windows and UNIX.

Examples of insane behavior of UNIX's lack of locking:

- A process can get its file corrupted because flock() is cooperative, so there isn't any enforcement that even if file locking is used, it actually works. Hence the dance with temporary lockfiles as workaround.

- A process can happily store important information into a file just to have it deleted under its feet after the usage count of the inode goes to zero, and good luck bringing the data back to life without forensics tools.

Quite sane indeed.