problem with password

I create the database by following:

mkdir -p /usr/local/pgsql/data
chown postgres /usr/local/pgsql/data
su postgres

initdb -D /usr/local/pgsql/data
postmaster -D /usr/local/pgsql/data
createdb appc
psql appc

Then i create a same user:

create user dima with password 'dima'
\q

Then:

psql appc -U dima -W
Password: __Input any password__ - enter to postgresql.

Why i can access to database with any password? What is my error?