Living in NYC this is one that I never get over. My in-laws live in the suburbs outside STL and we're headed there in a few hours. I know that the house will be ridiculously quiet when we arrive and have to prep myself to handle for when we arrive.

I used to live in a 1st floor/basement duplex ~50 feet from the #1 subway line. We could feel the train rolling by every 5-7 minutes (more frequently during rush hour). When the trains weren't running we noticed the quiet.

Quiet can be very disconcerting when you're used to the dull drone fo background noise.