Some years ago I travelled from AMS to HUY on a shorts 360 of the late AirUK. We boarded, a full aircraft apart from two seats, i was lucky having an empty seat next to me. We sat for about twenty minutes and then two guys who were almost paryletic fell on to the aircraft. The guy attempting to sit next to me fell in the aisle on his way to his seat, lots of effing and blinding. He sat next to me and smelled as if he had recently thrown up. I advised the flight attendant that I wasn't prepared to sit next to him, she replied that i had to because the flight was full. I said I would not sit next to him and if necessary would get off, after a few words where I seemed to be the baddy and the drunk butting in to ask me what my effing problem was. The two drunks were sat together and i was moved and sat in the other drunks original seat.
How they were allowed to fly that night was amazing and is my worst experience of such problems.