"it's not even funny" is usually added onto a sentence to increase the seriousness if the subject and to emphasize that "no, I'm not joking". People say it all the time without really considering it's meaning, though, which is why I called it a figure of speech.
Indifferent. But really, why does everyone bring it up if they don't like it? I mean, that's just making it plus populaire and plus discussed, and it's annoying...