In nearly thirty years of fairly frequent flying all over the place I cannot remember one flight that would come near the heading of "horror". A couple of flights in Soviet Poland were a bit worrying when I looked at the bald tires as we boarded. I suppose the worst one was a BA777 flight from Denver to LHR. When my wife sat in her middle seat, the seat back collapsed. I called one of the cabin crew and he manhandled the seat back into the upright position and she strapped herself in. As we accelerated for take off the seat collapsed again and I suppose this was a bit horrific. Again I called the cabin crew whose attitude suggested that he thought that having a serviceable seat was a bonus we weren't entitled to. The flight was full and there was nothing he could do. I eventually discovered that there was one free seat in business class and I suggested to the passenger in the aisle seat that we encouraged the cabin crew to let him move. They agreed to this so we eventually settled happily into our aisle and window seats with the space of the faulty seat between us.
Apart from that, the only possible moment of horror was sitting in the jump seat of a BA737 landing at Gatwick, The PF in the right seat flared for landing much too high and tried to correct by lowering the nose. Even I as a simple PPL knew that was going to be interesting and it was. Fortunately all three wheels hit the ground together, with a huge bump. The worst part was that my colleague sitting in the cabin had assumed that they had let me land it.