The teachings from our parents, teachers & friends.
But mostly, parents.
How you turned out to be, partly your choices for the many years you've been on earth.
I can't remember when I started to lie. Perhaps it was when I played the game hide-and-seek, perhaps it was when I was terrified of the consequences of telling the truth. Many other experiences could have been the contributing factor but it wasn't something that my parents thought me.
It was my own choice. I think it is true when they said the little ones says the darndest things but most of the things that you've asked them, they answered you with the truth. They don't yet know how to care for one's feelings as they speak their mind freely. What their parents told them about things. Like for example, back in my time, the Karung Guni man. Parents threatened their children into selling/giving them away to the Karung Guni man all because they wanted their children to behave properly. Thinking back now, some things does work into your upbringing.
I used to hate how my mum will pester me to be with her in the kitchen and help out whereas al my other cousins will sit & talk amongst themselves. I hated it because up till now, I never understood or ever talked to my cousins except the few that are close to my parents. And of course, there is another side to it, I am comfortable in being in helping in the kitchen during functions. It's okay to be mistaken to be maid just as long as no one treats me like one, I am good to go.
Well, my point is, whoever I turned out to be, never been 100% under my parents teachings. There are other factors like friends, own choices, experiences that makes me who I am.
And my parents never taught me how to be angry, mad, do not talk or even hate anyone.
I am thankful for that cause if they did, I wouldn't understand why as it'll hurt people so deep probably takes a long while to be forgiven.
For what it's worth, harping on this matter relieves my tension.
And yes, it all started out from you as parents :)