One of the problems I have, when writing Web pages, is the problem of cross-browser compatibility. I've moved recently to using a lot of CSS in my pages, as they give more standardized results — but unfortunately, some older browsers (such as Netscape 4) can't handle the complete CSS1 specification, let alone the newer CSS2.
It would be much easier for Web designers if (a) all browsers adhered to the standards, and (b) people kept reasonably current with their Web browsers. Of course, neither will happen.
But today, as I was browsing my referrer logs, I saw that somebody had visited running an ancient version of Internet Explorer under Windows 3.1.
Now that's just ridiculous.