A few months ago, prior to boarding there was a guy badgering the gate agents to give him an upgrade on a MIA-DFW flight (on a 777). He went up at least 10 times before boarding started trying to get an upgrade (I’m an elite, I have to have first class, etc). When they started explaining boarding over the intercom, he finally gave up, only to plant himself in the priority lane with his rollerbag by his side. When boarding started for first class only, he refused to move and forced everyone to kind of slide around him and his bag.
Unfortunately he got the battlefield upgrade after somebody missed the connection, and then proceeded to try and get people to switch seats with him so he could have a window. He was also demanding and a jerk to the flight attendants the entire flight.