My younger sister tends to get angry for somewhat trivial reasons. She thinks that I'm 'uncool' and will freak out at me if I sing/dance/do anything she deems 'too embarrassing' for her to be seen with in public. She has kicked/punched me on these occurrences. She's in middle school, so it's not like these are toddler tantrums. Does anyone have any advice for dealing with this type of situation?