Hurm, this reminds me a lot of the Rosie's diner that was in the book 13 Reasons Why. I don't know if you've read the book, but I adored it. So I can tell I'm already going to like this a whole big fat lot. I loved the prologue and stuff and how each of the rules ended in "No matter who you are."
I like the picture for the layout, but the background is a bit bright for my eyes.
I like the thought of Rosie's Diner. It seems like it could be a real place, which is always a good thing. The way the last line ties in with the title is also nice.
The prologue is short, so there isn't much to say. I do like the way you presented it, with the three rules and the repetition of "no matter who you are". I adore the milkshake rule. I just think it adds character to the place.
It's pretty short so far, but overall you did a great job on this.
Hm... this sounds like it'll be interesting. And I really love the layout. It just... pops. :P Can't wait to see what all you have in store for this! Definitely... subscribed! :D