What is good or bad behavior?

There is nothing good or bad but thinking makes it so, Hamlet says i the play.

We are made of the universe, but also of stories.
If many people will believe in a story it will be true for them.
Even if it will mean that you kill other people or animals.

But to work the stories must be corresponding to feelings.
To make soldiers fight they have to demonize the enemies.
Someone has to tell them that the enemies are bad.
That its best to kill them.
And there must be a reason for it; they are bad because....

What if we understand that it's just stories?

Then, is Shakespeare right?

Let' s see - if something is good there must be a bad behavior to compare it too.
God and bad are interdependent.
Let's say that we call it skilful or unskilful. Of course also interdependent.
But also interdependent of the culture around and what century.

What is good and bad changes.
Buddha is said to have eaten meet, Today in most Buddhist monasteries that is unskilful.

Nowadays we have enough green food to live a healthy life as a vegan or vegetarian.
But insects will die as long as we grow food, even if it is in a ecological way.

So it's probably impossible to be completely skilful on this earth, as long we are alive.
The best thing for the nature is to not be born at all, it is said.
But maybe there are some reward if you try to as good as you can, You never now.

Dostojevskij wanted to write about a totally good person, but he failed.
It ended in "The Idiot".
Maybe its not interesting to write about a good person, anyway he or she has to interact with not so good persons, as  "Mysjkin" in the book had; and that made him less good.

Ethics comes for the greek word for customs.
If we follow that its clear that they will change.

what about that different situations and different customs claims different actions?

Then we can never follow practises like Kant's categorical imperatives,  or utilitarianism.
Can we even say that democracy is the best for every situation?

Arete, another term from ancient Greek history means excellency or moral virtue, and Aristotle linked it with knowledge.
Maybe that's wise. Different culture and ages have different knowledge and therefore act different.
Aristotle meant that only mature people could have Arete.
So is that the solution for the riddle?

Of course not, but maybe the best answer so far.

But in other contexts, as in the Iliads, arete belonged to the heroes.

And Aristotle was  the teacher of Alexander the great who went to war...
Although he died young and not mature.

Let's say that Arete on our days means to stop unnecessary consumption and to decrease capitalism....
Then the corona - crise can be a step in that direction.

Then the old saying, nothing is bad without being good for something, right.

Or in more fair words; No cloud without a silver lining.
A mini story too, but maybe a good one.... ;~}

Let's end with a thought about the interaction between ethics and aesthetics ;
Let's say that the last variant of the saying has a lighter tone that makes the word a bit more beautiful.
And a world that is beautiful is more likely to be handled with careful hands, isn't it?