@OnlyheretovoteonAIBU
Poster asks question directed at one child families.
People with more than one child rock up to tell them they’re wrong and pressure them to have another...
Unless you’re going to bring them up for us then piss off, frankly.
This in spades
@AlternativePerspective
I can’t help thinking that the posters who come on to these threads to extol the benefits of having more than one child do so because they still question whether they did the right thing having more than one. Otherwise it wouldn’t matter to them what other people did, because they would be sure they’d done the right thing.
Exactly this. ^ I never see parents of 'onlys' ranting on at people with 2 or more children, telling them how 'wrong' they are to have more than 1 child. Yet I always see parents with multiple children bashing parents with just 1, whilst rambling on about all of the amazing things about having many children. Methinks they doth protest too much! I think they regret their choice and are projecting.
I got nagged and goaded to death by 3 work colleagues of mine when my DD (now mid 20s) was little, with them demanding to know why I wasn't having another. Apparently my DD would be selfish, lonely, spoilt, and I was selfish for expecting her to be my carer in old age. 
As for these 3 colleagues - two had 3 kids each and one had 2, and each colleague had nothing but trouble, constant trouble with their children. Constantly bickering and fighting, and they hated each other, and were pretty badly behaved.
I never had ANY trouble with my one child (daughter,) and found it very amusing and entertaining that they were trying to bully me into having more, when they clearly could not handle more than one child themselves! From what I saw of them and their kids, I was like 'no ta. Just one for me cheers!'
In addition, whilst I know several families with 3 to 6 siblings who get on well and seem close, I know WAAAAY more who don't.
Especially if it's just boys... (brothers... ) Brothers rarely get on. I personally cannot think of a single example where brothers get on really really well. In several families I know they tolerate each other, but I know LOADS of cases where they loathe each other, and once they hit early 20s, they part ways and don't stay in touch.
Why did I (and DH) have just 1? I am not going to discuss that on here (sorry OP,) but suffice to say, the reasons have been mentioned on here by a lot of posters.
And like many others with 'onlys' the dynamic between me and DH and our DD is perfect. We are a wonderful close-knit, loving family who always have each others backs. And I would never change this for the world.