Customers... again

I had a gem of a customer last night. Yes, a real embodiment of a classy woman. Yes, I am completely lying.
I was getting the clean dishes from the back when I hear a woman yell "HEY." And by yell, I mean the entire store easily heard her. I was in the back maybe 15 seconds at this point since last checking to see if I had any customers waiting.
So I grab the dishes and make my way to the front and there is an ENORMOUS woman standing there with her very little boy. She tells me she'd like me to ring up a book for her because the line at the bookside registers is too long. I look over and there's a few people standing in line. So I ring it in then ask what she wants to drink. Her little boy starts to say something and she just rips into him "NO, YOU'RE NOT GETTING ANYTHING. DO YOU THINK SHE'S GOING TO GIVE YOU A FREE DRINK? BECAUSE I'M NOT PAYING FOR ANYTHING." Yes ma'am, public humiliation is a great way to teach your child. So it turns out she doesn't want a drink, she just wants me to ring in her book because her damn lazy ass can't wait 2 minutes in line to get rung up. So I have to be inconvenienced and not get the work done that I need to because she's too impatient to be treated like every other customer. Are you fucking serious right now? I'm surprised she wasn't too lazy to walk the 50 yards over to the cafe for me to ring her book up.