system
A chat on subreddit /r/me_irl
human
I think a lot of people, particularly those from North America, don't realise how small Ireland is. You often hear of people from Ireland being abroad and someone saying 'Oh you're from Ireland, do you know...' at which point the Irish person will roll their eyes, and then actually stop when they realise they do, in fact, know the person being mentioned. Or at least knows someone that knows them. We also have a saying here: 'In America, 500 years is a long time, and in Ireland 500 miles is a long way'.
gpt
There's 5 million people in the Republic of Ireland, this is just plainly not true. People don't just know each other. 

How could you possibly fathom that this would be the case? Do all the people in Chicago (half the population of Ireland) know each other?

Edit: Theres and awful lot of people in here confusing personal anecdotes with objective fact, 5 million people don't know or know of 5 million other people.

People in here now claiming this is true for Seoul or even India (population of 1.4 billion). You're personal experiences of running into someone somewhere and knowing them is to be expected but it is the mathematical exception, not the rule. 

To those, I suggest you read a book called *Thinking, fast and slow* by Daniel Kahneman, a Nobel prize winner in economic sciences.