Never again!

When I was about 6 years old I went to the seaside with my family.
We usually spent a week there every year. Unfortunately, that was our last holiday there.
In one morning, I went with my mother to the market to buy some oranges, as we usually did.
-One kilo of oranges, please! said mum.
-Sure!
While the lady put the oranges into a bag, I was frustrated because she didn't give me one first, so I served myself.
-Where do you have that from, my dear? my mother asked.
I didn't answer. The lady who sold us the oranges proposed mom to weigh the fruits again. After the results, mom turned red because of the shame. She payed the orange and then we returned home.
She tried to explain me what I have done, but I didn't understand then. On the other hand, I knew that I mustn’t do that again.