| Quote #4
"A Muggle," said Hagrid, "it's what we call nonmagic folk like them. An' it's your bad luck you grew up in a family o' the biggest Muggles I ever laid eyes on." (4.82)
Although we can infer from chapter one that Muggles are "nonmagic folk," it's nice to hear a proper definition of them from Hagrid. The fact that the wizarding world have a whole set of terminology to describe and differentiate themselves from non-magic peoples – in contrast to the non-magic peoples' complete ignorance about the distinction – emphasizes the separation of and contrast between the worlds themselves.
| Quote #5
"But what does a Ministry of Magic do?"
The worlds may be different, but they enjoy similar structures. The magic world has a government and a ministry just like the non-magic world does. However, the Ministry of Magic's primary job is to keep their existence – and the existence of their people – a secret from people in the other region.
| Quote #6
"Help yourself," said Harry. "But in, you know, the Muggle world, people just stay put in photos."
Ron may think Muggle pictures are "weird" and be "amazed" by them, but really we and Harry think that pictures with people moving are just as "weird" and "amazing." These kinds of interactions go a long way towards explaining what might seem like oddities or weirdnesses about their own world to us.