Kyle has a chocolate bar in his mouth and he's chewing it as he walked in the house, immediately turning to ask his sister ( who's also your best friend ) without a care in the world.

"What's she doing here ?"

Of course, your best friend was annoyed at her brother being so rude and basically smacked him on the head until he went away. Kyle sometimes hated you being here. He kinda liked you and he didn't need his sister to know that.