my sis threw tantrum

my sister threw a tantrum (yh at her age) just because mum wouldn't give her forty quid for some skates that she will never use.
i got some ventro turbo the other week and now she wants some, the difference is me and my mates actually go skating, she won't.
she annoys the hell out me. why can't she respect mum a little bit. it isn't like mum doesn't ever give her anything. she bought her dance shoes for £50 which she never used, only to sell.
which is what will happen to her skates i just know it.
whatever i have she needs, not wants, needs. she goes to concerts without me and i give her my stuff but that isn't enough. i even tidy her pig sty (i mean room) for her and she never says thanks. i don't know why i bother. maybe it is because i have to live with her for a couple of years yet and i wanna sort of stay in her good books.