Customers and their stupidity/annoyance

So, last night at work, I wasn't the manager in charge, but Hope, who was the CSM for the night, was on break, so I was stuck with answering the phone, which usually isn't all that bad of a thing. But this one lady, who I believe to be German (her last name is Meinbach, and she sounds German) calls and complains about food she got around lunchtime yesterday. She starts complaining about how she got a strip salad, and her chicken strips are all oily. She also said the box her strips came in was oily. I don't have a problem believing the box got oily, or even that the strips were slightly greasy (though that is highly unlikely as well, they are usually on the dry side whenever I get them), but she said that there was oil running down her hand when she picked them up. I have never heard of that happening at Chick-fil-a before. Our chicken is never oily or greasy that I know of. Or at least not to the point of it running down your hand. And then she started dogging our Mexicans that work for us in the kitchen (that's why it was important that I mentioned that I'm pretty sure she's German). I wanted to yell at her. Our Mexicans rock. She went on some rant about how people who aren't from the United States don't realize that we have health problems and about how they don't care about following the rules that we have. Then she mentioned something about I would probably recognize her because she comes up here a lot. Sadly I know exactly who she is, and I always hate having to help her. It takes like 15 minutes to finish helping her, and I've yet to figure out why. She always order's a couple of kid's meals with no salt on the fries, and then usually complains that something isn't warm enough, or something like that. I told her, "Yes ma'am, I recognize your...", then she starts talking over me, as if I don't matter any. I ended up spending 10 minutes on the phone with her. It drove me crazy! I wanted to go off on her when she started being racist against our Mexicans. Seriously, they're awesome. Oh well, that's my rant for today.