Postgres Account Inherit Question

I've configured my 'pg_hba.conf' file to look as follows:

# "local" is for Unix domain socket connections only
local all all md5
# IPv4 local connections:
host all all 127.0.0.1/32 md5
host all all 192.168.0.0/24 md5

Now I've reloaded / restarted the PostgreSQL daemon however for some
reason when I use the 'postgres' user locally, it never prompts for a
password in 'psql'. I've altered the role to NOINHERIT

postgres=# ALTER ROLE postgres NOINHERIT;
ALTER ROLE

Any other role locally requires a password to even list the database
using 'psql -l' command except the 'postgres' role. Is this normal
behavior or am I missing something here? How can I force the postgres
account to be prompted for a password when communicating to the
database server locally?