NaCl(aq) - How far?

Jay: did you know that The Marianas Trench is almost 7 miles deep? It's the deepest part of the ocean.
me: I thought the ocean was deeper than that
I mean... that's really deep, but...
Jay: mount Everest would disappear in it
me: I have no concept of distance
Jay: ok so the trench is almost a mile and a half deeper than everest is high
me: well until today, I would have guessed that the ocean was like 112 miles deep
so a mile and a half doesn't seem like much
I also would have guessed that Everest was like 27 miles high
Jay: planes only fly at 7.5 miles
me: oh. hm
Earth in my head is apparently way larger than it actually is. Probably because I watch too many documentaries on outer space.
Similarly, I can't really weight the distance between 3 million and 300 million. Or 50 tons and 500 tons. Or 40,000 feet and 4 million feet. It's all "a lot."