Like a few other scenes, its sole purpose was to make Japan look like a weird, bizarre place, showing how alienated the main character felt- not speaing the language, surrounded by strange people (the guy making face at her in the taxi), needing other people to help her out. I hated the beginning and that scene, as it looked ridiculous- like the other females at the bar were clearly laughing at/commenting on Sara and her food, and she could not communicate with the chef- it was a pointless scene, like the rest of the film really.
In the beginning there was nothing, and it exploded.