https://www.tomek.cedro.info/why-linux-sux/
Даже хочется поставить "fun" topic, но тут не до смеха под Ubuntu:
# adduser user
Adding user `user' ...
Adding new group `user' (1000) ...
Adding new user `user' (1000) with group `user' ...
Creating home directory `/home/user' ...
Stopped: Couldn't create home directory `/home/user': File exists.
Removing directory `/home/user' ...
Removing user `user' ...
Removing group `user' ...
groupdel: group 'user' does not exist
adduser: `groupdel user' returned error code 6. Exiting.