If you do a Google search for “Creative custom 404 pages,” you’ll see examples of people who have customized pages that would have otherwise ended up looking something like this:
Bloggers often create customized 404 pages to provide a bit of comic relief to their readers, and prevent them from experiencing generic, unfriendly error messages.
If you have a broken link on your blog, or, a reader navigates to a page that’s temporarily down, having a customized 404 page provides your readers with a better user experience. Customized 404 pages are also a great opportunity to provide some help to your users by linking them back to your blog, or give a few pointers on navigation.
You can find the option to create a customized 404 page by going to Settings | Search Preferences. To enter your custom message, click Edit to open the text box. Type the copy you’d like to appear on the page, then click Save changes. If you’d like to get more creative than using standard text, you can use simple HTML or CSS (if your template has a style file loaded).