the difference in a "no"

I've said "no" to Caia several times. I had to use that word when she started pushing buttons on the dishwasher and when she started dropping food on the floor. I said it to her today when she let her apple juice dribble out of her mouth and down the front of her shirt. Typically she just smiles at me and finds something else to do.
Last week though, I learned that she reacts a little differently when her Daddy says no to her. Sam and I were sitting on the couch while Caia and Tru played on the floor. We both watched as Caia walked over to Truett and hit him on the back with a toy and we both immediately sat up and said, "No Caia!", in stern voices. And Caia turned and looked at Sam with shock and her lower lip started to quiver. Before I could even blink, she burst into tears, put her head onto the ottoman, and started to wail. I just looked at Sam and started laughing. Apparently, Daddy hasn't said no very often, if ever, and she did not like it. She lifted her head and, still crying, walked over to him and reached for him. She then needed to be comforted for several seconds before she pulled herself together. It was comical.
Who knew that the same word coming from two different people could have such a different impact? It's just another sign of Sam stealing her from me.