if i'm getting paid...let me do my job

Last night, I was working at Waldo's. This couple and other woman come in every week. Last night, being no different, the man orders a smoothie, one woman a chai, and the other an iced mocha. Apparently their daughter used to work here, so they think they own the place. As I'm making the drinks, the lady leans over to get the card-puncher, as she does every week and punches her card. I usually am a little annoyed by this, but am like "whatever." Last night, however, she leans over again and rings up her drinks!! I was about ready to push her back. She's like "where is the iced mocha button, is that the same as mocha?" I was like "just a second, I'll get it." She ended up finishing and then even pushed credit and ran her dang card through the machine, tears the receipt and signs it...all while I am waiting on her, making her drinks. We were out of whipped cream last night and I knew this might cause a stir with the man...he likes whip on his smoothie. I didn't even ask if they wanted whip (well I couldn't really since we were out), I just gave them their drinks. Of course three minutes later, he comes back and asks for some. I told him we were out and he responds with "WHAT?!" and knocks his hand on the counter. Ahh. I am still soo annoyed by the whole incident.