A pub/hotel in Sheffield, UK. I went there for a weekend conference a few years ago, and found this place online - it was very near the conference site and also really cheap...
The downstairs was a fairly grotty pub, advertising live music, and then there were stairs up to the rooms. It was a very tall old building and my room was on the third or fourth floor up. Each floor was shut off by a locked door from the stairwell, and the electronic room key also unlocked the door to the floor.
The room was actually reasonably comfortable, but somehow the atmosphere of the place creeped me out. I found myself eyeing the chair and wondering if it would be a good idea to wedge it against the door during the night, or whether this would leave me trapped in the room if there was a fire.
I checked with the staff about getting breakfast in the morning at 8 so I would have time to eat before going to the first conference session at 9. No problem, they said, so I went out for a meal, and when I came back the music had started. It went on until 2.30 or 3 am, and it was loud enough to be clearly audible in my room (3rd or 4th floor up). Eventually, I got some sleep.
In the morning, I headed downstairs just before 8 for breakfast. As I went down the stairs, I began to smell a very distinctive smell... (Gross alert!) Someone had clearly been desperate for the toilet and had tried going upstairs to avoid the queue. Since all the doors leading onto the stairway were locked, they had squatted on the stair and gone to the toilet right there. Both kinds.
(end of gross alert).
I made my way round the mess and went down to the ground floor. No-one was there and there were no signs of any breakfast arrangements. I thought I really ought to let someone know about the stairs, so I hung around until 8.50, when a staff member finally arrived. I told him about the mess on the stairs, and he seemed to think it was perfectly normal.
I decided not to make any mention of breakfast, and just grabbed an energy bar on the way to the conference site.
By a coincidence, two other conference attendees were staying at the same place, and in the end we bonded over how awful it was, so there were some positives, but I learned my lesson - if it's too good or too cheap to be true, don't stay there!