I recently observed something interesting from my son and decided to have this conversation with him to make sure my instinct was correct:

Me: Boy, do you always listen to what Daddy say or speak?
My son: yah

Me: Everything Daddy said or speak, you will listen?
My son: yah

Me: Everytime?
My son: yah

Me: How about Mummy? Do you everytime listen to everything she speak or said?
My son: errr…

Me: Only Sometime
My Son: yah

Me: So everytime Daddy say something, you will listen everytime and notice it, correct?
My Son: Yah

The conversation ended and it struck me that from that moments onwards, I MUST watch what I speak or say in front of my children or they will remember and follow what I say.