The CSS-Tricks front end is usually pretty darn fast, because most pages are cached (and don't need to be dynamically generated when requested). However, up until recently, the CSS-Tricks WordPress admin didn't have the same luck.
In particular, the post editing screen was slow. Painfully slow. Saving a draft took several seconds, which is enough to break your flow in the middle of writing an article.
Working on a tip from Pete Sorensen, who posted a performance question on the WordPress StackExchange (and was kind enough to tell us about it), I set out to figure out what was making the post editing page so slow.