The only "fast food" type I've seen mentioned here that I've eaten are Fuddruckers and Five Guys. It's Five Guys for me, definitely. I'm anxious to try In-N-Out when I head out west later this summer.
As far as restaurants go, I do enjoy Hard Times burgers as NMS alluded to.
That said, the deep fried "Heart Attack Burger" from Mother's in Fed Hill takes it for me... I mean just look at this description:
Beer battered burger stuffed with cheddar cheese, then deep fried and served with lettuce, tomatoes, onions, and chipotle mayo.
BTW, I seriously didn't feel all that great for about 20-25 minutse after eating one! 
“We have a shot at a wild card right now. But it is not a probability that we're going to win a wild card.” -2022 Trade Deadline
"It's liftoff from here" - after selling on 2022
"We're on a slight upward arc" - Winter Meetings 2022
"I think it's really hard to sit there and chart a course and say, 'We're likely to win the division.'" - Winter Meetings 2022
Mike Elias