Why say "never fails to disappoint" if what you mean "is reliably excellent"?
You probably meant something more like 'never fails to excite' or some antonym of 'disappoint'. Perhaps a good example of using too many layers of negation causing confusion.
Nancy was quoting the review given as an example of shooting yourself in the foot with too many layers in the linked Language Log post. The author of this review meant "is reliably excellent" and wrote "never fails to disappoint".
[I'd put this in an open thread, but those don’t seem to happen these days, and while this is a quote it isn't a Rationality Quote.]
— Geoffrey K. Pullum, Language Log, “Never fails: semantic over-achievers”, December 1, 2011
This seems like it might lead to something interesting to say about the design of minds and the usefulness of generalization/abstraction, or perhaps just a good sound bite.