1.
I’ve never been punched or hit or kicked! I think for people with siblings that’s surprising because siblings often get physical in their arguments.
Carrotpurse

2.
Wife and I are both only children – net result – our kids do not have any aunties, uncles or cousins… And we had a big family in part because we were only children!
borgata_rat

3.
Relationships are hard.
I’ve always envied people who had not just siblings, but siblings of the opposite sex. Growing up with an understanding of how the opposite sex thinks/feels about their body, about friendships, how they deal with fears and insecurities, and react to power-struggles among their peers… all that shit is a complete fucking mystery to only-children, and it’s an complete mind-fuck when you run head on into it in your first relationship.
duhvorced

4.
If you have trouble with your parents you don’t really have someone to talk to who is that close to your parents as you are and who understands like you do. So it is only you who has to deal with your parents’ frustration of life, their disappointment in you, their anger because you don’t live your life like they wanted you to do.
Smeman

5.
There’s no person of approximately my age in my family. I’ve got one cousin but she’s 20 years older than me so I’ve always percieved her like another aunt. Her children on the other hand are 10 and 15 years younger than me and we don’t even meet much.
Because of that I kinda cannot grasp the concept of having a non-hierarchical relationship with your relatives or basically having a relative who’s also a buddy of yours.
marquecz

Image Credit: nordicparenting.dk

6.
The fear of moving too far away because if something were to happen to either parent, there is nobody else to be there the way you can. Especially hard as an only child with split parents.
marceatan

7.
That when they both go you are truly alone. I don’t currently have a partner and my father passed 2 years ago. It’s just my mother left, I don’t speak to my family that live in the same state so if/when my mother goes and I’m still single then….I’m it…
I have friends, great friends but as for family mum is it
Charmed1184

8.
How your friends become your siblings – but for your friends WITH siblings you don’t become theirs.
Growing up (and still) I had/have a core group of friends – 1 is an only child and the others all had brothers and sisters. I feel closer to this set of friends than almost anyone else after 25+ years (even my husband) but I’m always aware that they have siblings who THEY are closer to than me. For me that’s the loneliest part.
Case in point – when I got married they were all bridesmaids in my wedding. But when they got married I wasn’t a bridesmaid in any of their weddings because they kept it “family only” for the participants. They had absolutely every right to have their weddings be precisely what they want, AND it was something I felt very aware of.
revolutionutena