Late to the party, but the accepted answer doesn't explain why no error is displayed. And as this is something Postgres newcomers often stumble upon, I wanted to add that.
TL/TR: always end your SQL statements with ;
Because the createdb database did not end with ; psql thinks the statement isn't finished and waits for more input. This is indicated by the prompt changing from postgres=# to postgres-#. An extremely subtle change that I wish psql would do differently (more "prominent").
By entering the meta-command \list the "current" SQL statement is "aborted" without executing it.
If the createdb had been ended with a ; the output would have been:
postgres=> createdb foobar;
ERROR: syntax error at or near "createdb"
LINE 1: createdb foobar;
^
postgres=>
Clearly showing that something was wrong.