Not sure how you equate fast food joints with "dives," they are much closer to the sterility of an Apple Store than a dive. Dives have character and grime, fast food joints usually do not.
I avoid fast food except when I'm on the road or in an airport. But man am I sucker for Popeye's. Delicious on the bone fried chicken, and their biscuits and mashed and gravy are great. If I'm in the South (which I am rarely) I may seek out a Bojangles. I think their chicken is even better than popeyes, but the sides are not.
When I was a kid my first job was at KFC. The original recipe ain't bad but I don't think I've actually sought any KFC out since I retired.
Panda express/manchu wok type places are pretty disgusting but at an airport I sometimes just can't help myself.