Years ago I stopped using iMessage because it was losing messages. Some messages were simply not delivered, with no error or explanation. I found this unacceptable, and it never happened to me with SMS. I understand that SMS is not end-to-end encrypted, but what's the point of encryption if the message never makes it from end to end? So I've been using SMS ever since on my iPhone and still do; lost trust is difficult to regain. Nevertheless, I started using iMessage again several months ago, but only on my Mac, in order to keep in touch with some people after I quit Twitter. This became my first real acquaintance with the Mac Messages app, which I had no reason to use otherwise. (I did use iChat extensively back in the day when AIM was popular.)
I've been sending messages exclusively from a personal email address, but the other day I needed to message a StopTheMadness customer, so I wanted to use a business email address instead. For some reason I had to add the new email address in the Apple ID pane of the app formerly known as System Preferences, rather than in the Messages app. Once I figured that out, I opened a new message and entered the customer's email address in the "To:" field. And then I… wait, where is the "From:" field?? Can't I choose from my email addresses, or even see which email that Messages has chosen automatically? In Messages Preferences (err, Settings), there's a "Start new conversations from:" popup. That's fine, and it's analogous to the "Send new messages from:" popup in Mail app. Yet every new message in Mail app has a "From:" field in addition to the "To:" field. You can easily switch your email address from the default. As far as I can tell, this doesn't exist in Messages app. Am I missing something? It seems like a bizarre oversight. Why would I need to open Preferences (Settings) every time I want to send a message from a (currently) non-default email address?
I actually did change the settings to my business email address before I messaged the customer. Honestly, however, I have little trust in Apple to do the right thing (see my lost trust above), so it would be nice to confirm with a "From:" field that the message is coming from the proper address. Another thing that confuses and worries me is the predisposition of Messages to put everything in a single window. You have to deliberately select "Open Conversation in Separate Window" to make it behave differently. Thus, I'm presented with multiple conversation threads in the same window, and I can only hope that each one is coming from the email address that I originally intended. There seems to be no way in the user interface to tell! If any of my readers know (and I mean know, not guess) a way to look at that information, please let me know.
Being the person that I am, I had to do some kind of verification. The good news is that there's a way to verify, though it's ugly, and of course it's in Terminal app.
sqlite3 ~/Library/Messages/chat.db .dump
In the SQLite dump you can see each message, with both the message text and the sender's email address. Messages did work right, to my relief. I just wish that I could see and change this somewhere in Messages itself. How do millions of people even use such a primitive app, and how is the app so primitive after 20 years of Apple working on Mac OS X and macOS?