A good & funny experience: I was flying coach, all the Army would authorize for official travel. When I tried to sit in my assigned 3-across seat, a husband & wife already in 2 of the seats wouldn't allow me.
The woman started screaming (and I literally mean screaming), that their travel agent has assured them they'd be all alone in the 3 seats, not have to share them with a 3rd person. Showing them my ticket only made the woman more hysterical, claiming my ticket was a misprint or something.
In the meantime I'm stuck standing in the aisle, while people are trying to squeeze past me to take their own seats. I motioned to a flight attendant, and explained my problem. She told the couple I had a valid ticket for the seat, and whatever their travel agent told them wasn't true, the 3rd aisle seat in their row had been sold. If they had wanted 3 seats across they should have bought them all.
The woman only got more hysterical, claiming a right to my seat because this travel agent (of which she had no proof) had promised it to her, though she hadn't actually paid for it. I had a valid ticket, and she didn't. The husband said nothing through all of this, looking rather embarrassed and sheepish in my view.
Finally I took the flight attendant aside and quietly said I really no longer wanted to sit next to these 2 unpleasant people anyway, and I would take whatever available seat there was to solve the problem and not further delay boarding. She said the flight was booked, but she'd check.
A moment later she pulled me by the arm, and took me forward into First Class. I asked if that was OK, and she said yes, you sit here on the aisle. I turned around and gave that woman passenger, who was staring at me from coach, a big smirk, as if to say: "Thank you bitch, you just got me a First Class seat. So go take your 3-across coach seating and fuck yourself."
The best part was that the plane was still boarding, and was indeed over-booked. So that the flight attendants eventually forced the couple to surrender their precious 3rd seat to another passenger, anyway. While I got to fly in 2-across First Class, which included a full meal with free drinks, something more common 25 years ago. (To my credit I told the First Class Steward when food service began that I was bumped up there, in case I wasn't entitled to the meal perk. She said if I sat in First Class I got to eat & drink First Class
Meanwhile the coach couple got peanuts and paid for whatever drinks they had in crowded 3-across. That was definitely a best experience.