To quote wikipedia’s entry on Hitchhiker’s Guide To The Galaxy’s Marvin, The Paranoid Android:
Marvin is afflicted with severe depression and boredom, in part because he has a "brain the size of a planet" which he is seldom, if ever, given the chance to use.
Thank goodness the 2005 film version of Marvin had a spherical head, perfect for some kind of planet gag!
Penned as “big Bad Bubba” - c.2005 - back before changing to ”Bort”.