I just encountered the worst Help file I've ever seen, and that includes student projects from my days teaching Online Documentation at Southern Poly.
The content pane and the pane for displaying the TOC, Index, and Find (Find? as in can you say WinHelp.exe?) are two separate panes, and the TOC pane is modal!
Click to see enlarged version.
Not only that, but the Help is written at the microtask level--no insight as to how do I use this product to do something useful.
OK, so maybe this is some restaurant management software or some other application written by someone with no concept of user experience.
NO! This is a product designed and distributed by a company in the usability business--one whose product is meant to help you design usable software.
In all fairness, the product is way cool and works pretty well, but why do usability companies get all the way down to the user assistance level and then suddenly get usability stupid?