12. See Full Size Images Immediately
Hover lets you roll your mouse over images on Google, Facebook, etc, and see the full-size photo without clicking to expand it.
13. Re-open Accidentally Closed Tabs
Cmd + Shift + T. If it's not already burned into your brain, memorize it, because those are the magic keystrokes that will bring back a tab if you mistakenly close it. You're welcome.
14. Hover Your Mouse Over to Translate
Instead of running to Google Translate at the first sight of a foreign word, use the TransOver extension. It'll tackle any language, and it'll do the same okay job you've come to expect from the guys in Mountain View.