Why do people look down on you if you work at McDonald's?

I just got hired today at McDonald's in my town, i'm a 20 year old female, and i've heard my friends talk crap about people that work at McD's. Even my boyfriend says it's crap basically...he says that working at Chick-Fil-A has the high end people work there. So would that make me low end to work at McDonald's? I have also have a facebook, and I really want to put on there that I work at McD's, but I know people will judge. I know they will. But times are tough these days, and this is my second job. And from what I've seen, all my co-workers are very friendly, they have a good appearance, and it's not a bad place to work for. Yes, it's fast food, and yes, McDonald's is not the healthiest food to eat...but still. It's really not that bad. So what makes it so different from any other fast food restaurant? ):