So you're going to a place where women typically serve you something, and they don't put orders through to other people (They make the stuff, then serve it to you). She isn't alone, because you're going to address the employees as though they are a set.

This works at dunkin donuts, dairy queen, rita's ice, coldstone creamery, etc.

Address her friends, "Hey guys, look. I just found out I have this amazing power. It's something like mind control."

Turn to the target, "I'd like a medium coffee light and sweet."

Turn back to her friends while she makes your stuff and say, "Look! It's working!"

Almost guaranteed to get a laugh.

_________________
Our work is never over...