It’s a bit selfish, but if I take the time to show up early and get a seat I am not going to make myself uncomfortable because you feel entitled. I’ll move a bit if there’s room, but if half the seating area further away is open then you can sit your late ass down there.
One time at a movie, a friend and I stood in line before the movie to get good seats in the center where wed have a foot rest and no one in front of us. Dude came in late with his kid and wanted us to move. My friend told him to fuck off in many words loud enough for the theater to hear.