I hate drawing backgrounds. I put so much effort into it and in the end you hardly see it anymore anyway. >>
This all started with a little doodle I literally scribbled in less than one minute during a Constitutional Law lecture (which is why it looks so horrible): [link]It's German, by the way.
I sorta liked how it looked, so I decided to draw that again, actually trying to get the anatomy/proportions right.
/EDIT: Of course I didn't design the background myself! I watched a few episodes and picked a tree here, a bush there ... then I redrew and altered it whenever I felt like it.