"Assume that every person you meet will be the most important person you will ever meet. The man in front of you won't have a sign around his neck showing his salary, or job title, or what kind of car he drives. You won't know if the next woman in line runs a Fortune 500 company, or is a millionaire investor, or is closely related to the owner of the company where you work."
The point is to assume that all guests are VIPs. As a result, you will truly never make a distinction between how you serve the "extra important" guests vs. every other guest. Everyone deserves excellent service, regardless of their socioeconomic status, job title or any other label.
Takeaway: Always give your best, and assume that everyone else is worthy to receive it.