The afore-mentioned Best Western in NOLA is hands down my worst experience in the US. An experience in Panama City (Panama, not Florida) rivals it, though.
I found this motel in a guidebook. I guess it was a budget-type motel, I don't really remember. It certainly wasn't a chain or anything like that, one of those places where the clerk is behind a window in the lobby, and whatnot. My room was on the third floor, and the hotel probably had 8 floors. The room itself was fine, big for the price I paid, and it had hot water, decent TV, etc. My window looked onto the street.
At some point that evening, I was watching TV, probably getting ready for bed, and heard a loud commotion in the hallway. I opened the door, stepped into the hallway, and saw several firefighters running up the main stairs. No alarm was going off, of course. So I went back in my room, grabbed my wallet and my passport, and went downstairs as soon as there was a break in firefighters. There were a couple firetrucks on the street, and a crowd of people gathered outside the restaurant across the street. I went across the street to join them, saw some smoke and fire extinguisher foam, and about a minute later, a charred mattress comes flying out of a room a few floors above mine.
The firefighters hang around for a little bit, then finally drive off, leaving the mattress laying on the sidewalk. People started going back inside the hotel, so I followed them. I got to my floor, and in the little side hallway nearly right outside my room were two gruff-looking guys and a couple women, who I could only assume were pimps and hoes, based on their mannerisms. I realized they hadn't seen me, so I went back downstairs to the restaurant across the street, and sat inside for a while and ordered something to eat. After about an hour, I figured it was safe, and went back to the hotel. Sure enough, they were gone. Locked the door, slept a bit on edge that night.
I had planned to spend another night in Panama City, but found a nicer place to stay that second night.