is this a bug or I am blind?

[Mage <mage(at)mage(dot)hu>]

online=# select * from common_logins where username = 'potyty';
uid | username | password | lastlogin | status | usertype | loginnum
-----+----------+----------+-----------+--------+----------+----------
(0 rows)

online=# select * from common_logins where username like 'potyty';
 uid   | username | password |         lastlogin          | status | 
usertype | loginnum
--------+----------+----------+----------------------------+--------+----------+----------
155505 | potyty   | board    | 2004-08-16 17:45:55.723829 | A      | 
S        |        1
 60067 | potyty   | board    | 2004-07-07 20:22:17.68699  | A      | 
S        |        3
174041 | potyty   | board    | 2005-02-17 00:00:13.706144 | A      | 
S        |        3
(3 rows)

online=# select username, username = 'potyty' from common_logins where 
username like 'potyty';
username | ?column?
----------+----------
potyty   | t
potyty   | t
potyty   | t
(3 rows)


psql 8.0.3, Debian.

      Mage