Outlook 2013 is one of the most controversial products inside the Office 2013 / Office 365 product suite. The interface changes Microsoft made in Outlook has left it awash in bland whiteness and streams of rarely-used ribbon buttons. The folks over at ComputerWorld have published a helpful guide to getting the most from Outlook 2013.
You can check out their article here: http://www.computerworld.com/article/2472297/desktop-apps/161639-17-ways-to-make-outlook-2013-suck-less.html
One of the best tips from them regarding the whiteness: To choose between blinding and merely brash white, click (or tap) File, Office Account. Then pick the color that jars you least from the Office Theme box. The change you make will be reflected in all of your Office apps. No, you can’t change just Outlook — Word, Excel, and PowerPoint get it, too.