I'm the younger sibling but I feel older because all of the dumb things my brother has done. Some of his problems are so obvious but whatever thats on him. Also evey now and then he'll get into his pissy the world is against me attitude and be mean to everybody when he's the one starting stuff. He will come over the house talking about me and then say I don't treat him right. I just ignore and keep going though because it's not even worth it.

My brother is sort of like that, but he is actually older than me. You can't really tell most the time, though. He is really immature. ;0
My biggest problem with him is he doesn't want to have to do anything, unless there is specifically going to be something in it for him,
and even then it's not guaranteed that he will do it like he said.
And my mother lets him get away with acting that way, which is what really gets me.

My sister is usually just really bitchy and crap. She can be loving sometimes, but I barely see her anymore because she's always at friend's house or something.

Oh god. I have a problem with my OLDER brother. I am SIXTEEN and he is 30 for goodness sake. What the hell is he doing trying to sabotage my life.

First he tries to convince my mother not to buy me a prom dress so that I can't go to prom.
Second, he gets mad everytime my mother and I go get pedicures.
Third, my mom fixed my laptop for my birthday and my brother said "Mom, that's like giving a ferrari to a 13 year old. Give me her laptop and I'll give her my old computer."
Fourth, My mother is buying me a car because she is moving out, and my brother is furious. He wants to take my new car and give me his old one. I need a car to get around if my mother wont be here.

He doesn't even live with us anymore! Why is he trying to take everything away from me? GRR!!!

i don't have any younger siblings, but my boyfriend has a little sister that is obsessed with me. she just became 10 but she acts like she is 3. she is rude as anything and when asked if she will leave us alone, she flips out and tells her mother that i was rude to her, even though i ask politely. SO annoying.

My brother and I get on quite well.
I'm about a year older than him, but we have the same interests/attitudes toward most things.
Theft of each-other's clothing is the biggest problem, but we're both guilty of that, so it works out pretty well in general.
He's my only sibling, though, so I guess I can't really comment on other situations.

my sister always tells me "i can do whatever i want"
sigh - -'

My younger sister is mental I swear. I'll ring home and be "hey is Dad home yet?" And she'll go at the top of her voice, "NO!!!! HE DUSNT GET HOME TILL 6! OH MY GOSH" blah blah etc. So i'll just hang up.

aww poor you. I'm an only child so I have no stories to share :(