The killer is that it's a one way street and as the eldest you eventually twig that while you were expected to be the bigger person and rise above everything at say age 7, when your younger sibling reaches 7 you're still being told that they're too little to understand and you need to be a good big sister and give them part of your share even though they had theirs earlier/ not complain that they took or broke your things / give up your quiet reading time to entertain them because they're bored etc.
Absolutely, notnow. In fact, never mind aged 7 - this went on all of our lives. When I was 50 and my youngest sibling was 42, she was still referred to as 'just a baby", who needed to be indulged and cosseted and protected because "she was young" and I was expected to go along with the whole charade.
I was always the "sensible" one (I had to be) who had to "understand" - and I had a clever, pretty sister, an artistic, pretty sister (the baby) and a brother. I didn't stand a chance.
And yes - I was and am bitter. Even now it upsets me when I think of those wrongs of the past, pathetic as it may sound. It meant that I had nothing of my own, because it could be taken off me and given away at any moment (and usually ended up, as you say destroyed - or often given away by a sister to one of her friends). And I was never allowed to voice a protest because that was spiteful, apparently - not to want you things taken from you. (You are supposed to share with your siblings, and you HAVE to love them).
I am sure it contributed to my lifelong depression.
(Oh dear - I'm getting weepy now. Please excuse my self-pity. Some things never stop hurting.)