When an oncoming car gives way for me I raise my hand in acknowledgement. It's a second of politeness. I don't even need to take my hand off the wheel. I expect oncoming cars to do the same when I give way. Not sure what the % of people who do is, but a lot of people don't. Given our congested roads today I think both giving way & saying thank you are such small gestures I can't understand why so many people don't do it. Are they just rude or arrogant, not concentrating, or are their minds on other things? Who knows. But it is irritating.
Both data and public perception suggest that people have become more impolite in the 21st century. A Pew research paper found that nearly half of adults believe public behaviour is ruder now than it was before the pandemic. They found that social isolation during COVID-19 caused interpersonal skills to atrophy. Also on line disinhibition has changed manners & etiquette. Traditional rules are disappearing. Heightened political and social divisions have spilled over into everyday interactions, reducing baseline empathy toward strangers.
The Pew survey defined rudeness as public behaviours ranging from cursing or playing loud music to smoking & taking photos of people without permission. There seems to be a "tit for tat" response, insults or rudeness provokes insults or rudeness & negative interaction can escalate. Hopefully not if you are in a car though. Although I do remember extreme examples of road rage.
There have always been rude people. Another piece of research said that " these individuals are amoral (or immoral) hotheads who refuse to accept criticism or correction from others. They may also—though less reliably—be low in behavioural inhibition, high in behavioural activation, “blirtatious (quickly and openly expressing their thoughts and feelings to others), narcissistic, and/or Machiavellian".

I wondered if rudeness is learned behaviour. As I thought it is. Children learn by imitation & modelling. So the parents or guardians have a huge impact on behaviour. Apparently rudeness spreads like a virus. If others in your group are rude you copy because you want to belong.
The corollary is that manners, consideration & politeness have to be actively taught to children by those nearest & dearest. In my experience if you smile & are polite you stand more chance of receiving similar behaviour. Being rude, abusive, inconsiderate & impolite will just result in that being the behaviour you receive.
It's a vicious circle which is all too common.

