Biggest annoyance for me was the lights and noise. Haven't spent much time in big cities but I clearly remember the lights and noise. At 2AM there were still, heavy trucks, blinking lights, sirens, people talking, headlights swinging past the windows, traffic, commotion, streetlamps humming, and people clomping up and down the stairs. Fairly quiet at 4AM it never got really quiet and it never got dark.

Living in the country I get country dark and quiet. Nature isn't silent but you can hear crickets and sometimes even an owl quietly beat the wind flying close past my window. And you can always tell when larger critters, including humans, approach because the crickets and tree frogs go silent.