There is no "common sense", but there is a common ideal standard that everyone expects everyone else to follow - but themselves. For example when driving, people are expected to drive steadily and in a specific distance from the edge of the road. Non- compliance creates frustration for everyone else, who see their expectations challenged.
The thing is though, if we are the ones doing it we can come up with a million excuses why. This is the root of all misunderstandings in the world: we judge ourselves differently than we judge other people. We have the leverage of knowing exactly what went wrong.
Obviously, every single person acts the way they do because their personality has been sculpted by unique factors, as you mentioned as well. So we can't always "excuse" peoples' negative actions just because they might have been stirred by trauma or hurtful experiences. But we can maybe try to put ourselves in their shoes just for a moment; perhaps this way we wouldn't all be so harsh with one another.
Awesomely put. Actually you might have explained it better than me.
You explained it really well :) Actually you mentioned something that I had never thought about before. I always assumed that the relationship between age and a not-giving-a-fuck attitude (very funny graph, btw!) was only due to the fact that young people interact through social groups while older people already have their own uniquely sculpted personalities and go their own merry way. But what you mentioned is also true: young people, although in larger social groups are also more "selfish", in the sense that they expect more of other people than what they can give back, and this comes from the fact that as a child, you have everyone catering for you. So obviously you get more frustrated when people don't act like you'd want them to!
Glad our perspectives meet then.
it's funny how humans grow to understand their own tragedy.