For instance, how did they come up with a particular shade of blue to use for a specific toolbar? 
A designer had picked out a blue that everyone on his team liked. But according to tests conducted by a product manager, users were more likely to click on the toolbar if it were a greener shade of blue. After this dilemma, Google tested 41 gradations of the competing blues to see which ones consumers might prefer. Just blue? I don't think so.
Another tidbit of interesting trivia. Ever wonder how Google came up with the minimalistic home page design? 
Thank Marimekko prints for that inspiration: bold blocks of saturated colors against a white background. This design is the brainchild of Marissa Mayer, Google's director of consumer web products (essentially Google's gatekeeper). Her aesthetic runs towards clean and simple, mirroring her childhood home and current penthouse in San Francisco which is painted in neutral hues and decorated with colorful pieces by Dale Chihuly, Andy Warhol, Sol LeWitt, and Roy Lichtenstein.
A lover of simplicity, coupled with vibrant color and a touch of whimsy...now that's my kind of designer!