It's the lot of most eldest children; to look out for their younger siblings, protect and reprimand when necessary, and dig them out of the various holes they've dug for themselves. This doesn't stop once everyone is past childhood.
Nothing illustrates this more beautifully than the pained letter sent by an eldest child of four siblings to Brisbane library this week, which was posted from Melbourne with a book to be returned.
Beleaguered 'Kurt - the oldest sibling,' began the letter with a request.
"Please find a book from your library that was left at our house in Melbourne by my little brother Mark. Whilst you may have the right to impose a late fine, I am requesting that you apply your discretion and waive the fine. The reason for this request is that it really wasn't his fault, it was mine."
With the readers' interest well and truly piqued by this last sentence, we all just have to know why the fault rests with the eldest brother.
"You may ask how this can be when I live in Melbourne and Mark lives in Brisbane and I have never been to your library, or checked out a book from your library."
And here's the clincher.
"The reason is that Mark is the youngest of four children."
It's a reason used over and over to explain the often baffling, inconvenient and irreverent actions of the youngest child, who knows there are almost unlimited people around them to sort out any messes left behind... like a library book from two states away.
And like all eldest children, who always have to do the right and good thing, Kurt is there for his brother. And like all eldest children, they find a way to enact revenge- there has to be some way after all, of getting a little satisfaction from an unjust situation. In this instance, it's public humiliation.
"While the youngest child is often outgoing, fun-loving, creative, social and love being the centre of attention, they often grow up feeling entitled because they get spoilt and are used to getting things their own way. In addition, they are less intelligent than their older siblings and require their older siblings to take on their battles leaving them unable to care for themselves adequately."
Yeah ouch. We can see where this is going.
"This is the case with Mark. So, when he left our place after Christmas it was me, the oldest sibling, who should have checked that Mark had left nothing behind. I failed ot do this and as a result your book was left behind in Melbourne."
The letter has certainly given fans of the Brisbane Libraries Facebook page something to giggle over, with some hoping that after the efforts of poor Kurt, the fine was waived.
Others took the opportunity to weigh in as fellow eldest children, fully identifying with the Kurt's noble task of getting his little brother out of hot water.
"Kurt raises a valid point here, and I totally agree with him... being another oldest sibling."
Now the big question is whether the library will actually fine Mark. There will no doubt be a few who believe he should be made to finally learn his lesson.
And then there will be those who, like Kurt, would do anything for their younger siblings, no matter how tedious.
Essential Kids has contacted Brisbane Libraries for comment and await their reply.