Few days ago I had situation like that. My morning flight was cancelled and everybody rushed to the check in area to change their flights. I was number two in line and I patiently waited my turn. Then when I approached the agent some lady just put her ticket on the counter ignoring me like I was invisible. That pissed me off. I’ve told her politely to move back.
The afternoon flight was full because of the cancelled morning flight. I had aisle seat so I was happy. Guess who got the middle seat next to me? The same woman from the morning. She was kind of heavy set and her guts were spilling allover my seat.
Then she asked me: “Would you mind switching seats with me? I like to have space around me”
My answer was “NO” – case closed, short and sweet. She didn’t talk to me during the flight.