> You're going to occasionally get drug dealers (or other habitual criminals), aggressive dog owners, serious mental illness cases, couples that have screaming arguments every night, motorcyclists who rev their engines at 5:00 AM, etc.

I'm not downplaying how much those suck. but half of those problems go away if you don't have to hear them. The couple that argues at all hours of the day? How do you know they're arguing if you can't hear them? If there's a dog that barks all day long but you can't hear it, how is that a problem? Not all of the problems go away, yes, but some of them go away if apartments are built better.