Being nice is in your best interest. I thought of this when I saw the story of a passenger who was trying to make a connecting flight after her inbound aircraft was delayed.
She says she ran to the gate with her baby. Apparently she was traveling with other family members, the flight was about to close and she got into an argument with the gate agent. When she took a photo of the agent’s name tag, the agent instructed her colleague to close the door early. Another passenger arrived, they opened the door back up for that passenger.