Being good in life is not bad

First question when we say 'Is not bad to be good' is what is definition of good or bad? Or at least how this can be measured: how much something needs to be bad to be more bad than another, or what is it which or who gives definition of bad or good?

Seems like we can easily answer all these questions starting with what is the definition of good or bad.

We can imagine a kid who is three years old and put this kid in a situation in which he does something bad—let's say he breaks his mom's flower vase.

We can say by the expression of the kid that he knows very well destroying the vase was a bad thing to do, and you close the discussion right there and presume we already know the definition of good and bad from moment we are born.But this is totally wrong. The kid has this reaction because of his family's reaction, and breaking the vase will only be understood as something bad when the people around him give him pushback energy.
So, based on this example, we can presume bad or good is determined by pre-existing society members and is a collective decision about what the difference is between the two. This collective moral code progresses and changes by epoch, and in different places in the world, we have different ideas. An example of this is monogamy, which is spread in most countries, and polygamy, which is spread in Islamic culture and other parts of the world. Both societies think their approach to marriage or how men and women should make their connections is good. Doing monogamy in a polygamy country will be considered bad, and doing polygamy in a monogamy country will be considered bad.

So, who is right? No one.

Now we will get frustration by the reader, and a pure, hard-swallowing example is needed.

When we kill someone, is it bad?
Asking this question, we come right to the point and the conclusion of all we were talking about here.

Let’s try to simplify the answer as much as possible by giving an example.

Let’s imagine a world in which we have four people. Two of them are very attached to each other; the other two are the same. One day, one of them deci  des to kill one of the other two. First, we need to understand he can’t come to this thought because he never saw someone kill someone, so he doesn’t know it is possible.
But let’s say they are not the first people, and their mother died by the bite of a snake, so he knows if the person he hates gets bitten by a snake, they will die. So, he catches a snake, risking his life to delete another life, which is mostly the case, then lets the snake go when this one is sleeping, and the snake bites him. He dies. His friend wakes up and finds out he is dead, crying, feeling lost, screaming. Then the killer realizes he has done something bad, and there you go—bad is formed.

Or we can say our killer knew this was bad because when he lost his mother to a snake bite, he felt the same pain his victim's friend was feeling.

So simply, bad is determined by experiencing bad, which is over years implemented in our moral idea. The same is for good—the first time experiencing good determines this is good, and then it is implemented in a societal code which will preserve its idea about bad and good and evolve by time and change.