What's with the lamp at the beginning of Pixar movies?

Have you ever wondered why there is a desk lamp that seems to have a vendetta against the "I" in Pixar?
Well here's where it all started.
(This video does not shed light on where the lamp's gripe with the "I" comes from however)


If you ever visit the Pixar Animation Studios you will see a giant model of Luxo Jr pictured here.
The picture comes from a Pixar studio tour taken by collider.com's Matt Goldberg.  See all the pictures of his tour here.
See how the lamp lights up at night here.
Watch a tour of Pixar studios:
Part 1
Part 2
Part 3

There is a great book by David A. Price about the origins of the Pixar company called The Pixar Touch.
I actually listened to the audio book.