Worst chain restaurant - well, there are so many, but my vote has to go to Outback. Someone mentioned a "cup of salt" in every Macaroni Grille item. You can double that for outback. I'm not salt adverse, but everything at Outback on multiple trips was so salty that I couldn't eat it. Even the SALAD was salty.
Worst local restaurant - Bistro 100 in Chicago (well, it is part of a small Chicago group, but still qualifies as local). Trip 1 - so bad in every respect that we wrote the management. To their credit they issued a large credit toward a return trip. We went and received the VIP treatment. Service improved immeasurably, but you can't hide bad food. Nothing good to say about this place at all.
Oh - let me add a vote for Emeril. Emeril's in NO was a disaster. We were seated in the room with the wine coolers, with my back to them. Everytime someone tripped over me to open the door I got hit with a wave of mustiness - Yes, I know its humid there, but must in a wine cellar is NOT a good thing. This summer I was forced to go to NOLA, and actually had a decent meal, much to my amazement. Emeril seemed to have his staff fairly well trained, something that is not typically true in NO at this point in time.