Atlanta. Nothing about this place is good.
The lights, the muzak, the inefficient seating (why all the footrests?), the unavoidable constantly-running tvs which resulted in me being fairly convinced that I had actually contracted the flesh-eating bacteria, the veggie lo mein that actually resembled an unnatural spaghette bolognese (the only thing Asian about that mess was the name), the lack of Starbucks or any other coffee/tea shop, and the fact that you have to walk half-way down the terminals (ten minutes) before you hit the bank of screens that tell you where your flight is leaving from.
It can be depressing if you're doing lots of travel to the Deep South, as Atlanta is the major midway point for everything in and out of the region. However, the Charlotte (NC) airport is also a possible connecting point, and I highly recommend it. Clean and bright, no tvs, multiple speedy Starbucks, and a respectable sushi bar.
(Please note: I'm not a Starbucks person, as I'm not a coffee drinker. But Starbucks is reliable in that no matter where you are, you know exactly what you're going to end up with when you purchase something. As per what you purchase, I recommend an Earle Grey tea with added vanilla syrup and cream. They might be momentarily confused, but it'll always work out. They'll put the vanilla in, and you add the cream yourself. Tasty!)