I understand how sibling rivalry can be rampant in childhood. They live in the same house, and sometimes in the same bedroom. There are limited resources, so siblings get territorial.
But when siblings become adults, they are unlikely to live with each other anymore. So what on earth do they fight about?
Inheritance
Silly, petty crap that gets blown out of proportion. Add to the mix that some siblings might not see each other on a regular basis, so that little issue from a year ago never really got resolved, and it festers until one person thinks the other’s snide comment was directed at them, and suddenly you find yourself in the middle of a fight. It’s worse than middle school.
My sister and I don’t usually ‘fight’ but if we do it is about communication; either one of us has communicated badly or not called for awhile (I am most often the offender).
Since we are grownups, it is all usually resolved by a quick (few minutes) chat.
I’m not sure how “grown up” my aunt is… but she has “fought” with her older siblings (uncle and dad) for many years, going on and off. Right now, her relationship with my dad is manageable, once again. In their case, they had very similar personalities, with little patience and a lot of miscommunication.
Nobody in the family, except my uncle and her, knows exactly what the fight between them has been in the last few years. HE used to be the one who was more agreeable to her when she was spiteful to my dad.
Inheritance
Parental favor, inheritance
Lifestyle choices… especially once one has kids who must be “properly influenced”
Properly influencing the grandchildren in front of the new grandparents
Loving and doing “enough” for the nieces and nephews
Who goes to what family holiday (for family unity, For The Children)
When and where to do joint vacations (for family unity, For The Children)
Who has to haul ass to visit the other (for family unity, and you don’t expect them to drag the kids to YOUR house, right?)
The same old crap they picked on each other about when they were kids
My sister and I don’t fight. We’re pretty good friends, even.
From what I’ve observed in other families it seems that when adult siblings do fight it’s often connected to the parents. Someone isn’t helping them enough, or is taking advantage of them. Responsible, employed brother might fight with ne’er do well brother who sponges off parents. Or “good daughter” who stayed local and takes care of parents might resent a sibling who left town and never looked back.
Who has the responsibility for taking care of the elderly parents.
My barely-younger-than-me sister and I rarely fight and are very good friends, but the last time we had a huge argument it was over the fact that she was openly hostile to my ex even though I made a really big effort to become friends with my (exceptionally quirky) brother-in-law. My ex turned out to be an asshole (still love him in a way, but that’s why he’s my ex) so I guess she was vindicated in a way and I apologized to her for being defensive. Still, she tends to go about these things in a very high-handed way at times and it really pisses me off.
I tend to let the minor annoyances etc. go, because I’m sure that I bug her in some ways too.
The one other thing that used to piss me the hell off occasionally was what I saw as her supreme flakiness…like she’d ask me to drive out to see her and my brother-in-law in the city and they wouldn’t even be there for 30 minutes. Or the time I told them I’d take them out to dinner and we had a huge fight because she showed up with some other random friends in tow and I didn’t want to pay for them (or rather, my mom threw a fuss about me paying for them). When she graduated from medical school, my whole family showed up to the graduation on time and she only got there 1 minute before she walked. It was mortifying and so disrespectful…she had her gown but one of her classmates had to toss her his mortarboard.
I eventually discovered that every single time she did something flaky that pissed me off it had to do with her mother-in-law going batshit insane (including at her own graduation and insisting they go find skim milk). My sister is trying to avoid being dragged into her MIL’s crazy which results in her attempting to deflect rather than putting her foot down and saying no-the big reason being that her MIL is genuinely mentally ill.
Frankly, I feel a lot of sympathy for her and my BIL on this front because dealing with mentally ill people isn’t easy, so I don’t fight with her when she occasionally does these flaky things now. It must be hard enough that our family comes off sane and nice and his mom comes off crazy and crazy (his dad is great, though) and my mother constantly pointing it out (not so nice mom, knock it off).
In my experience, children. My brother and sister fought constantly as kids, and now they get miffed with each other about their kids. His kid said so and so to her kid, she thinks his kids are stuck up, on and on and on. The kids get on great, as it happens.
To me (I’m the baby, so have always kept out of the sibling rivalry), it just seems to be a progression of their childhood animosity. My sister is sensitive, my brother is INsensitive… so it doesn’t really matter what it’s about.
My brother and I are quite close. He works for me (but we work in separate locations). We’re 31 and 33. We don’t fight ever, because it would be really bad for business. The only time we ruffle each others’ feathers is when I am trying to give him financial advice and he refuses to heed said advice.
My mom and her sisters…they don’t “never want to speak to you again” fight anymore. But they do get grumpy when one won’t follow the others’ advice. Mostly about money.
You grow up with somebody and there’s no hiding. They know all your weaknesses, all your foibles, and how to push your buttons. And sometimes when people grow up they don’t want to give up being the boss (oldest child), the peacemaker (middle child) or the Princess (youngest child). This dynamic can make for interesting get togethers.
Most grown-ups don’t take advantage of the power they have over each other, but some do.
My sister and I are good friends now, but used to fight a lot as kids. Thing is, there’s still no one on earth who can push my buttons faster than my sister and vice versa. Sometimes just the tone of her voice in one sentence of conversation on the phone can make me seethe. And with just a single look, I can get her red-faced and frothing.
But it’s not hateful fighting; we consider it normal sibling fighting.
So I guess the answer is: Everything and nothing at all.
So true! This totally nails the relationship between me and my sister.
This was one of the things we discussed after our last huge fight a couple of years ago (even though I loathe those types of emotional talks) and we’ve both actively worked to try to minimize it.
In the case of my sister and me:
Good personal finance practices, especially when she has hit up me or other family members for money because she frittered away her own and/or refuses to look for a job and/or is evicted for non-payment of rent and ends up living in my mom’s dining room with her husband and son (long story, as you can imagine). Or wants me to take her to rescue her car, which has been repoed.
Roles in life-cycle events: she wanted me to be a bridesmaid when she got married, because she’s a traditionalist. I on the other hand didn’t want attendants at all when I got married, and she is still basically not speaking to me because of it
In the case of my mom and her sisters: caring for my grandmother and her affairs, especially as my aunts are within a short drive and Mom is 1200 miles away, but still wants to second-guess their decisions
Treust me, you don’t need to live with someone to have him/her annoy the crap out of you. In fact, the person I live with is the person who is least likely to annoy the crap out of me 
Instead of the term “fighting” let’s use the term “stress”. You don’t have to be in an all-out war to experience plenty of tension.
I’m in my early sixties, with spouse, siblings, and siblings-in-law of comparable age. At this age, tensions are mostly generated by care-for-the-parents and care-for-the-siblings questions. Mom’s running out of money: who can chip in how much to help? Who physically goes to her place and helps her out? How much extra cash should those who can’t physically go to mom’s place fork over? What about the ailing siblings who can’t really take care of themselves anymore - what do we do for them? What about those of us who aren’t as well of as the rest of us - how much do we adjust the “chip-in” value for those folks?
In my case we’re all lucky in that everyone gets along. But that doesn’t mean there still isn’t plenty of stress to go around.
My brother and I had one argument that I can even remember. He really is one of those types who hold it in, but he bitches to me about his life and I bitch about mine, so I’m guessing like me he’ll bitch about ME to his spouse. I know I do things that really irritate him and I think both of us have a problem with how we’re raising our daughters but we keep silent for the most part.
The argument was about my grandfather. I was trying to work and take care of a man who hardly knew who or where he was anymore, who just wanted to die. I was overworked and overwrought at the time and I accused my brother of not helping me when it wasn’t really his job. It wasn’t mine either except I’d volunteered. I wonder now that he’s volunteered to take care of our father if he thinks I should help out. I won’t because my father is a horrible person who hurt me as a child, but my brother seems to be more forgiving.
The rare occasions that we fight, it’s mostly when my brother drags me into the thick of fights between him and our mom. Exibit A.
My older brother and I get along, in the sense that we have no stress or arguments. He lives 1000 miles away and his life almost couldn’t be more different than mine. When we communicate, which is rare, all is well. My younger brother and I are more rocky. We have gotten along extremely well at times and have met in the middle (he also lives 1000 miles away) for vacations on two occasions. None of us have any kids. We share interests and sense of humor.
This younger brother lives alone and seemed to go through some sort of midlife crisis over the last few years, with many people, including me, having trouble with his new crappy attitude.
I spent two years as our mother’s Power of Attorney, spending a great deal of time maneuvering her money around so that ultimately we would all get equal and substantial amounts. In the end, I needed a piece information from my younger brother to wrap up the last insurance policy, which I had working diligently at for 8 months after her demise. He wouldn’t give me that information, preferring to call the stranger at the insurance company with it, and thereby bollixing up the whole thing, causing confusion at the insurance company and giving them a new person to pepper with forms and more reason to delay paying out.
I let him know that I thought he was an idiot (may not have used quite that word) and was not pleased with my months of work with that insurance company being wasted because he trusted a stranger on the phone with information that apparently he thought that I was going to post online or otherwise misuse. After I spent years securing him a tidy sum he would not have otherwise had, and being quite financially secure without any inheritance anyway.
He responded by telling me “Do not contact me ever again for any reason.”
And I’m fine with that. So I guess we aren’t technically arguing any more.
I really don’t fight with my brother, but we’re quite far apart age-wise. He’s 34 and I’m 23.
We don’t really ‘fight’ but we get on each other’s nerves when it comes to the health of our parents. Our parents are in their 60s and just have way too many health problems. He’s closer to Dad and I’m closer to Mom so we each take one under our wing, so to speak, but it’s hard. My brother had to be harsh on Dad with his alcoholism and now he’s been sober for around a year. But Mom has some major weight issues to deal with, and I just can’t play the bad guy. She’s my mom, yo. So my brother thinks I need to put more pressure on her.