Offline Mode

Why are a lot servers running on online mode? I HAVE to play on offline mode servers because my dad said he cannot buy minecraft premium because they ask for a password he does not want to give so I really want to play on a offline mode server :( Please, there was an awesome offline mode server I ALWAYS went on but now it is online mode so I am really bored now. Help me :( The servers that are already running are REALLY REALLY REALLY BORING AND HAS NOTHING TO DO ON IT.

If you have a running offline mode server please PM me. I will join and I will be good.

Thanks for everyone's kindness.