The codenames for every major Debian release are named after characters from Pixar's Toy Story franchise. Debian's unstable release is fittingly named after Sid, an unstable character from the Toy Story movies.
I love the Linux world's tradition of less serious names, in general.
I guess when the OS is free, you don't need to get the marketing people involved as much.
The kernel was almost named Freax. Then there's GNU, Slackware, KDE which was originally the Kool Desktop Environment, The GIMP (released 1 year after Pulp Fiction), ...
It's often due to the devs creating it as a hobby project and giving it a light-hearted name to show it's nothing professional or important - and then it becomes important later.
My favorite right now is RebeccaBlackOS, which is the only current distro built around Wayland's reference compositor Weston, showcasing all the capabilities Wayland has.
Unlike Hannah Montana Linux, it has no Rebecca Black theming at all. It's just called that because the dev is a fan of hers.
Obviously a matter of taste and not trying to insult anyone but I never saw the appeal of the Toy Story movies and, adding the Steve Jobs link to Pixar, this is the ONE thing I never liked about Debian
Other than that I used it for YEARS with no issues whatsoever. Debian is honestly rock solid.
I only gave it up when I built a bleeding edge machine (it was bleeding edge for a whole 2 months maybe? hehehe) and I did not trust myself modding it enough to allow for super fresh drivers and other software.
I am now on Garuda Linux which is pretty awesome but I still miss good, solid, old Debian