[Rory and Lane are in the bathroom. Lane’s hair is bleached blonde.]
LANE: It’s weird.
RORY: Like straw.
LANE: I feel like I should be singing ‘If I Only Had a Brain.’
“If I Only Had a Brain”, a song composed by Harold Arlen with lyrics by Yip Harburg, for the 1939 film The Wizard of Oz, previously discussed and frequently mentioned. In the film, it is sung by Ray Bolger, who played the Scarecrow, imagining all that he could achieve, if he only had a brain instead of straw stuffing in his head (just as Lane feels that her bleached hair is like straw).
There seems be yet another dig at blondes here, that dyeing your hair blonde automatically makes you brainless.
The Annotated Gilmore Girls 