Manners are so very important. They completely change an interaction and can set the tone for the whole situation. My mother never excused bad manners and being rude was a capital crime. She once kicked my middle sister out of the car in the way home from dinner and made her walk the remaining mile home because she was being a rude bitch. I think she was 14 at the time ( no worries, safe neighborhood and my sister is over 6ft lol). My mother did not play around and all 3 of us girls say yes ma'am , thank you, no thank you and please even to the person taking our order in the drive through.
Ha- good decision, Mom^^^.
Just a couple of years ago, driving back from visiting my dying mother, my brother, his son and I stopped at a roadside diner for lunch. My brother (a physician) was acting so arrogant, walking around talking loudly on his cell phone to one of the other docs about my mother's VERY PERSONAL physical issues, causing the few other people there, TRYING TO EAT to glare at him. Then during our meal he went on an on about how the visual arts (yes, I make a living as a visual artist) are not as important as music (his son is a budding composer and pianist.) Yeah, playing out the old roles of me being the dumb younger sister, and him knowing better. Even his son couldn't believe how rude he was being...
Finally, when my nephew and I went out to the car while he paid the bill, we just took off; we just looked at each other and said, "let's go."
About a 1/2 mile down the road, my brother caught up with us and climbed in without saying a word...