Top on the list??
“Why did no one tell me that when I moved to NYC, I would have so many more boogers?”
I really never thought about it.
The dirt in the air seems to be the reason.

other warnings transplants wish they had been told
“don’t pick up “female” prostitutes between 14th and 30th Streets on the westside.” [no, this was not posted by Elliot Spitzer]

“don’t tell the guys talking in the movie theater to ‘Shut the fuck up’” [sound advice unless they're over 80]

“You have to actually pick up your feet when you walk…the pavement and sidewalks aren’t always flat.”
[huh? you mean in other cities, they shuffle??]
anyway, you can follow the link above to read the entire article, or feel free to add your own here.