Ok... i hate this when it ouccurs but why?

hi My mom and i sometime get into a little fight but this is what happens once my dad told me that i could give these imp. papers to his managers ok.....so my mom give me some papers and i do, but she told me to give it to this manager but if she isnt there then leave it on his table but there was another Doctor who was sitting on my Dad table and was concerned if he will take it and i give it to another manager but of my dad cuz i know them. So i tell my mom and she goes SHOUTING why did u do something i didnt tell u to do, how do i prevent from making my self stupid. ps WHY?