I have a Five Guys near where I work that I go to for lunch maybe once a week. There's a cute girl behind the counter who makes sure to always smile at me and say hi- and she knows my name because I often order online and carry lunch out. More recently, it's jumped up a notch where she's flirting with me pretty brazenly. I can usually expect her to wink, shake her hips a bit, shake her chest a little, and tell me she looked forward to seeing me. All while smiling.
As a result, I almost always leave a tip.
Tell me: what's the difference between this and prostitution?