One of the things that has continually bothered me in the past couple weeks (as a new Retina Macbook user) is the lack of favicons that support retina devices.
Apple has really been stepping up their game in the past couple years where screen resolutions are concerned. They now offer a plethora of devices with extremely high resolution screens, which is awesome!
I've been pretty unhappy with the navigation menus and administration interfaces in Drupal, so recently I've taken upon myself the task of improving Drupal 7's admin UX.
I've had headaches in the past trying to render a Drupal menu with not only the parent links, but also all of their children. I've used modules like Nice Menus in the past but it's kind of a messy solution if you just need to print sub-menus.
One of the things that has really bothered me about Drupal in the past is it's lack of page templates for content types. In some ways it makes sense that they wouldn't include the ability to make page--content-type-name.tpl.php.
Here pretty soon I'm going to start a blog about theming Drupal, and a few tricks/tips I've discovered over the years of working with this awesome beast. :) Please stay tuned! It's comin' really soon!!