Saw this elsewhere and in my mind it's quite true and a tad annoying.
I'm single and my siblings are married and some have kids. It never occurred to me that I buy them presents singularly ( out of a much smaller pot!) And I get joint from the couple or " the family" I'd never given it much thought and I dont have more than a twinge of annoyance because It's my choice what to spend and I like gift giving especially to nieces and nephews but when it was pointed out I was abit ahh I'd never thought of it that way