The most uncomfortable was when we were in an all-suite hotel near Cleveland Clinic. My MIL was having cardiac surgery so we rented a 2 room suite with 2 queen beds and a double sofa bed. Day 1, took MIL to the hospital, they prepped her and took her to the OR, we went to check into the hotel. Hospital called, surgery canceled until 6am the following day. We already had 6 of us in the hotel room, now had MIL too, so I slept in a wing-back chair with my feet on the bottom of the sofa bed so MIL could have a bed. I slept the same way for the following 2 nights as DH's other siblings were in and out to visit/stay over. I can sleep just about anywhere, but after 3 nights of this I was ready for a REAL bed!
The WORST ever was called "Honey in the Rock" motel in Beckley, WV. I was driving from NC to OH with DD, who was about 4 at the time (so maybe 23 years ago). It was late at night, pouring rain, and there was "something" going on in the area so all the hotels were booked. I'd been driving for about 9 hours and was exhausted. This place was a NIGHTMARE. Filthy, smokey, the rugs were crunchy, and there was no way we were using the tub/shower. I put toilet paper on the seat to use the toilet and got towels and blankets from the car to cover the bedspread so we could sleep. As soon as I got about 5 hours sleep, we were OUT of there. It was filthy, disgusting, gross.