Not flying but I can relate to being possibly being rude but more accurately wound up.
The event was a dirty area and my whites covered in soot. I was wound up and wanted satisfaction. A gentle smile and "let us launder them for you" defused the situation.
So, rather than the SLF that is looking for any excuse to exert authority or seek redress, a simple and effective response will often defuse the situation.
Back to flying, the whole process of getting to the airport on time, packing, unloading the car, trolley and bus to the terminal, the queue to checkin, the queue for security, the strip search (I exagerate), the 'interminable' wait after the boarding now call, all add stress to what may be a stressful situation.
OTOH, we were bused to New Orleans some 6 hours before scheduled departure and 7 hours before ATD, (I have moved New Orleans down to bottom of my favourites). I guess by the time we were boarded any rudeness and aggression had been bored out of us.
All credit to the crew, with a 160kts jet stream we made up time lost.