richinstyle.com also has a bunch of stylesheet resources, including a bug table
and a test suite.
anybrowser.com has resources and advice about making sure your web pages comply
with standards and will work well with all browsers (not just
the one you happen to use).
The World Wide Web Consortium (W3C) has a technical report,
Common User Agent Problems, about common mistakes browser designers make. This isn't
of much practical benefit to anybody who doesn't design web user
agents, but at least if something Netscape or IE does frustrates
you, you can check here to see if it frustrates the W3C too.