Reality: if you have a slightly non-standard accent, you will be shouting at your device five times before anything happens. While I could just have pressed the play button on my Apple TV remote and be done with it (no fiddling with a phone necessary).

Then there are all kinds of cultural realities that are apparently not considered in Silicon Valley. My favorite five pet peeves:

(1) Our family name is 'de Kok'. Very often these assistants totally mess up when I ask e.g. to call family (either they start complaining about dirty language or literally search for 'cock').

(2) We are a multilingual family, languages used in our household are German, Dutch, and sometimes English. None of these voice assistants work with multiple languages. So, the only alternative is to choose one language and stick with it. Unfortunately, if you choose English you are having a hard time navigating in Germany, looking up a German TV program, or calling a Dutch or German friend. If you set the language to German, you forgo looking up shows on Netflix by their English titles reliably.

(3) Usability goes down the drain once you have kids. Voice assistants typically do not work well when multiple people are speaking at the same time. If you are lucky, they are just confused, if you are unlucky they start doing whatever they infer from a semi-random mix of words. You cannot tell your three year old to be quiet, because mom or dad has to tell Siri what to do. (I use Siri sometimes, and our daughter currently likes to scream 'hey siri' repeatedly when I use Siri.)

(4) Voice assistants are unusable in most environments where there are other people.

(5) Voice assistants, especially in-house voice assistants are a potential privacy violation. So, you have to ask people that visit you if they are OK with your conversations being recorded (accidentally or intentionally) and switch off the device if they do mind the latent spying.

tl;dr: voice assistants only work well in monolingual families where all of the family members have a perfect accent and where none of your acquaintances mind the privacy violations.

Edit: added some more annoyances.

Edit 2: heavy downvoting :/. Please explain why!