I need some ideas on what i should say in this play.

Hello everyone, I need some ideas for a play I will be doing in a group.
The teacher put 6 people in a group to act out behavior. The leader of the group choose to make our play on the different behaviors in a restaurant.

So there are 6 parts for 6...

people.

1)The waitress - this will be my part
2)The ghetto girl
3)the manager
4)the police officer
5)someone with long term memory
6)someone with short term memory

The thing is, they said that, we don't need to practice what we will do and you should just come up with a response off the top of your head. I mentioned to them that we will probably mess up because for acting, you are given lines to rehearse and there are no pausing trying to think of an answer to give, which is what will probably happen since all they did was give each of us our parts without preparing a skit. The teacher will be giving each of us two grades, a group grade and an individual grade. So even if our group messes up, I'll have a good individual grade so I need to act my part out well.

My part as a waitress is that I will be nice to the rude ghetto girl customer and I will eventually get frustrated and get rude with her also. ( I am also supposed to scream at her but I don't think I can since I'm the quiet type and will probably look weird. Also what are some rude funny comments I can say to her since I can't think of any. No cussing and we will be doing this in front of the class.

So everyone (except the waitress, manager, and the police officer) will be sitting around the table with their menus. I will walk up to them and say, Hello, are you ready to order? I will take each of their orders and when I come back with their food, the ghetto girl will be smoking and I will tell her it’s a no smoking restaurant. She will respond by saying, I don't care what kind of restaurant this is, Did you buy this cigarette? (she said she's going to say that when I tell her not to smoke. So I will respond nicely to her and then get rude after she don't put it away. What rude comments can I say?

Also as for the other two parts: one girl will have short term memory where she will order something and then forget what she ordered and the other girl will have long term memory where she will talk about everything that she remember from a long time ago while she is ordering. I will also be nice to them and eventually get frustrated with them also. So what rude/frustration comments can I make to them?

I want to act my part out well and I would like some ideas. Thanks to everyone in advance.