Good article! I like the "official/unofficial" terminology.

I suspect a lot of those "unofficial beliefs" are about ourselves, how people judge us, what we can do, what is ok, what is offensive/insulting, etc. - at least, most instances I can think of were of that kind. "I [i]know[/i] so-and-so didn't deliberately act that way to annoy me, but I'm still as angry as if he did.", "I [i]know[/i] that girl isn't going to laugh at me, but I'm as nervous as if she was", etc.

This ties in with Akrasia ("I know writing my thesis is more important than watching falling goats on YouTube, but my behaviour shows otherwise"), and self-delusion (If It' trying to make myself believe I have high-status, isn't it like trying to make it an official belief even though part of us knows it's not true?).