Sharing a wall means becoming a recipient of whatever sounds and smells my neighbors (whom I cannot choose) decide to let emanate. My family has lived in apartments/townhomes and had to deal with, among other things:

* Deep wall-shaking bass music

* Game show TV turned up to the highest level, at 3 in the morning

* The smells of fried rotting fish heads

* Power tools

* Continuous dropping of items ranging from silverware to books to unidentifiable large metal objects onto tile (shared ceiling)

* A vast variety of sex noises

* The smells of sewage backed up into a bathroom

* Horse-like foot traffic on a set of shared wooden stairways late into the night (drug deals going on upstairs)

Never again. Yes, you can have shitty neighbors in the single-family-home suburbs but the extent to which they can ruin your quality of life is reduced.

This depends a lot on where you live. I've rented a few apartments that were cheap, by local standards, and learned exactly why this was. Loud obnoxious neighbors, who liked getting high and playing techno at 3 am, or having sex in the middle of the ground floor garden, or going crazy and screaming crazy stuff for hours.

But then I bought a decent apartment in a decent neighborhood and had none of that, and later traded it for a row house where every room has a wall shared with a neighbor in an even better neighborhood and now I pretty much don't notice my neighbors at all.

+1 to most of those on your list.

When I lived in Mountain View, my apartment was located on the middle floor. I consider myself a night owl, but my neighbor who lived upstairs liked to practice playing the drums at 5 AM in the morning.

You can call the cops on that. Even then the landlord would probably kick them out for a higher rent payer as well.

this is the correct answer

Most places in most countries have noise ordinances, not to mention rental agreements that prevent that