When dealing with client recommendations for design, usability, and accessibility, we always stress the importance of a custom 404 page. Why? Because I think everyone gets a little sick of seeing standard pages that do little to direct users toward a useful solution. These boring, default 404s are not friendly, they're hostile. And without the proper presentation they risk scaring away less savvy visitors who might not be content to just hit the Back button and get over it.

I stumbled across a witty custom 404 page this weekend. Though an extreme example (and slightly stupid) Livejournal's server error made me smile: