ssh won't ask for password unless i force PubkeyAuthentication=no

Lately I noticed that when I want to ssh to a server using a password I need to specify -o PubkeyAuthentication=no or I won't be asked for a password and the authentication will fail (well, for all I know, setting some other option may work too).

I use password authentication only once on freshly installed servers/vms, so it's not a huge deal, but... it still bothers me (mainly because I don't remember which option to set).

Do you guys have any idea what it may be?