I know there are other threads regarding Siri but I thought I would start a unique one. I have come to the conclusion that Siri is inconsistent an unreliable. Case in point, on my mobile devices I can say “Hey Siri remind me of this” and it works perfectly by creating a reminder in the Reminders app. However, if I try this on my MBP I get the following response, “I don’t see an app for that, you will need to download one.” 
A week ago this worked properly on all of my devices.
What gives Siri?
Last night all was well. Siri turned off the bedroom lights on command. This morning Siri says “the bedroom is not in your home. I give up.
“The bedroom is not in your home” is an all-timer response. Got a genuine chuckle out of me.
We just invested in some smart Lutron switches for our house during a reno this summer. We have a TV room, which I labelled “Home theatre” in the app. Any time I ask Siri to turn on the lights in the home theatre, Siri turns on the lights in every room in the house. The phone stops listening after it hears “home,” so I now just ask Siri to turn on the lights in the theatre, rather than the home theatre.
I agree with the common sentiment that Siri is maybe the worst assistant one could ever have.
“She” is better than a two legged one I had back in the 90’s. But that’s not a ringing endorsement.
BTW, she found the Bedroom without any help from me. 
I have just had to replace the two Homepods I have with Echo’s, as my wife has got fed up of Siri, so we’re back with Alexa.
It was that or get rid of the smart home fixtures I’ve built up slowly!
Failed the wife test 
I just teach her what to do when she gets stubborn like that.
For instance “Open WordBook”.
“It does not compute in my computer.”
So I show her what to do, quit the app and make my initial request all over again. And it usually works.
I mean, another way to look at it is that inconsistency is the sole reason anyone is frustrated with Siri. If it was consistent, then even if it got things wrong—consistently, you could compensate by adjusting your commands to its liking or plain avoiding it. Just like it doesn’t matter how discordant your oven temperature is with reality, as long as you know your oven.
True, but in this instance the inconsistency is between platforms. I suppose I’d rather have Siri consistently wrong across all platforms than inconsistent in being wrong from platform to platform. At least in the first instance I could adjust consistently. 
In the latter I have to modify my approached based on platform, which is, to put it mildly both frustrating and unproductive.
Along these lines, my car only does Bluetooth for the iPhone. It does have a microphone which works with Siri commands…sometimes. Sure wish it always worked, especially when I set out on a long trip!
Are you sure it’s about platforms? I’d say you’d never have made this post if it hadn’t been working on the Mac last week and no longer working on the Mac this week. No argument it’d be better if all ovens had the same temperature but it was one oven going all over the place that sent you over the edge.
Yes, the problem is that invoking Siri to remind me of an email has been working perfectly on all of my devices until this week. And then for some inexplicable reason Siri decided not to remind me of emails on my Mac but instead instructs me to download an application. It is really quite bizarre. I am running the latest versions of OSs on all devices Which includes a 2020 MBP M1, iPhone 13 Pro Max, and 2021 iPad Pro.
I agree. HomePod Siri is definitely less intelligent than iPhone Siri. Why Apple would fork a project that was already struggling is a mystery to me.
I find that Siri words better on my iPhone than on HomePods.
Could be environmental noise, distance from mic, or computing power - not sure.
I can say “potty” to my phone and have, probably 99% success rate, whereas HomePods are maybe 90%. My girlfriend has 99% success rate with HomePods.
(BTW, “potty” turns on outside lights for the dog.)
Siri is only inconsistently frustrating because Siri cannot be consistent in anything!!! 
That being said, I’ve largely given up on Siri for home automation, and I’ve started using an Echo Show.
This week I installed a bunch of smart lights in the kitchen (which work with Alexa but not HomeKit).
Sometimes when I say: “Alexa, turn off the kitchen lights” she replies “There are several items that share the name ‘kitchen lights’ which one did you mean?”
Other times, she’ll just do the thing that I obviously intend.
Why? No frakkin’ clue!
Out of frustration I went into preferences, turned over Siri related off and then recalibrated Siri on the MBP. “She” seems to be working correctly again.
Best all time response to “call my husband”. “I don’t know who your husband is. I don’t even know who YOU are…”
Turns out my personal phone that knows me had run out of battery and the work phone that doesn’t know me as well had picked up the request and tried to answer.
Another good one, from a few years ago. I had Siri working on my phone only, and my iPad popped up a message saying essentially "I can do something new, try saying “Hi Siri.” So I did and got a sort of Monty Python argument between the Siri on my phone and the one on the iPad.
Some other Siri fails:
If we keep posting Siri fails there is no limit to the number of responses we may get. However. . .
Last night while I was cooking dinner I heard what I thought was my neighbors laughing loudly outside my living room window. Things started getting rowdy and women were nearly screaming as the laughing continued. Then I heard one man yell “Happy New Year”. At this point I decided to investigate.
All the racket was coming from my HomePod. I have no idea what Siri had chosen to play or why “she” was playing it at maximum volume. When she ignored my “Hey Siri, stop” I pulled the plug and ended the party.
That made me laugh!
20…
All right this one is really annoying. If you add a friend e.g. Jane Doe to your contacts, you can tell Siri “take me to Jane Doe” and it will set up navigation to Jane Doe’s address from your contacts. Good.
Now try the same by adding a company to your contacts. Siri will never find it. For a company, Siri will only ever look up the name of a company in its database, never in your contacts.
Any time you’re going somewhere and try to prepare in advance by adding the location to your contacts - sure to fail if it’s a company.
I asked Apple about this years ago, the best advice they have is to add a person’s name to the company and request navigation to the person. This should not be necessary.
The other day I was dictating and said the name “Judy”.
I have 4 people named “Judy” in my contacts, and 1 named “Judie”.
It chose “Judie”.
My wife’s name is “Tracey”.
I have no one else by that name, by any spelling, in my contacts.
Siri/Dictation always spells it “Tracy”.
NO, BAD ROBOT.