I went on a tour of the Yuengling Brewery, and part of the operation was located in underground caves because of the year-round cool temperatures.  This was especially apparent on a hot summer day, when the outside temperature was around 100°F, but the underground temperature was in the 60s.  Maybe I missed this in home ownership class, but why don't we live underground?  I could think of a few possibilities right off the bat: 

1. Bugs.  My crawlspace is full of cave crickets, which look like giant black spiders and like to jump on my back as I enter and exit.  But I feel like this is a problem with a solution.  Either utilize some bug traps or just seal everything off.
2. Air.  Ventilation might be an issue.  Use a fan.
3. Plumbing.  The whole reason plumbing works is because toilets and sinks are vertically higher than septic tanks and sewers.  You'd need some sort of pump system, but this isn't a deal breaker.
4. Flooding.  Water likes to travel downhill, and caves don't really have a downstream exit.

So obviously there are some drawbacks to living underground.  But there's one simple benefit:  Temperature.  It's cool in the summer and easier to heat in the winter.  The mole people were onto something. #lifestyle