Switching text editors and needing to re–learn all the colors for syntax highlighting.
Cross browser compatibility, does it even exist anymore?
Dreamweaver templates. Need more be said?
Accidentally pasting HTML into a CSS validator and wondering what “Parse Error Lexical error at line 1, column 3. Encountered: “D” (68), after : “<!”" means.
(It means you pasted HTML into a CSS validator, oops).
Compatibility Mode in IE8 being used by people who don’t understand what it’s for.
"Look at everything that’s wrong with this page when I click this button!"
Figuring out which clearfix to use. There are a ton of ways to do the same thing!
When you can’t control the display of Facebook plugins that everyone has to have.
When you feel like you should support IE8, but can’t find a computer with IE8 on it..