Non-fiction ratings

I use the following subjective ratings to classify my non-fiction consumption. In the perfect world, all my reading would fall into ratings 1 and 2 (with the odd 3 now and then, as the mood takes me).

1: unmissable

Blew my mind. (Or just a "classic" text that needs to be read.)

2: great stuff

Has depth: good ideas, well put together. Changed my world-view

3: worth reading

A good account, worth the time I spent on it. But nothing necessarily earth-shattering or paradigm-shifting.

4: passes the time / mind candy

I read it, but it did nothing much for me: maybe I thought its style was turgid, or its content was shallow, or incomprehensible, or wrong! Or I just wasn't interested in the subject.

5: waste of time

I read it, but wouldn't have if I'd known... (It might have been saved from unfinishable only because I read it in a single sitting, probably skimming bits: if I'd been interrupted, I might not have picked it up again.)

6: unfinishable

This book fills a well-needed gap in the literature.

-- unknown

I couldn't finish it because it was so bad, or so boring, or so wrong, or whatever. Or I just found it too incomprehensible to bother with. (I classify more books as unfinishable that might have been just a waste of time a few years ago, as I have less time to read, so tend to be more impatient.)

"I want my money back. And my two hours. And my initial mental state"

-- William December Starr, rec.arts.sf.written