Reading this reminded me of when I had a reserved seat on a train a couple of months ago. I have a bad leg and the airline seats don't seem to have enough leg room so I always book a table seat.
I also find that if I book early enough and am very nice to to the clerk at the booking office I can get the nice seat, next to the window and facing direction of travel 
On this occasion a very up her own arse cow was in my seat working on her computer, all her gear was spread over the other 3 seats.
When politely asked her to move she refused telling me there were plenty of empty seats (all airline types) and she was 'working'.
I had to sit with in the airline seat across the aisle from her with my leg sticking out asking louder and louder for her to leave my seat until the train manager appeared.
The ensuing argument between her and the TM was actually funny, she
started to have a go at the train company and how unfair it was she pays £1000s every year and someone with an advanced ticket who has paid less gets her seat, it was disgusting, etc etc.
The TM after hearing her rant looked at me and just said to me first class is two carriages along and is empty go and sit in there and I will be with you in a minute. When I told him I couldn't afford to upgrade he just said no problem.
I spent the next couple of hours sitting next to the window facing direction of travel in a large comfy seat.
I saw the woman on the platform when I got off and thanked her for making it possible for me to have such a pleasant comfortable journey.
Which must have really annoyed her as I also saw the TM to thank him again and he told me that at the next stop he directed a lady with two small children into the three empty seats next to the woman didn't look like she got much work done 