You used to not be able to get a security clearance if you were a homosexual because you could be blackmailed. That's stricture has been dropped and that specific thing is no longer an issue mostly.
One of my favorite features of plan9 is how it handles the bin directory.
For one, you can have sub-directories inside the bin directory. This lends to a nice hierarchy of commands and encourages writing small single purpose commands instead of large monolith commands. An example of this is the `ip/ping` command.
Another feature uses the union file system which prevents me from having to mess with $PATH locating commands.