Though Messages has its quirks, I've been lucky to avoid most of them — I haven't had my message history disappear, nor have random contacts popped in or vanished out of thin air. I've rarely had problems with messages not being received or erroring out.
But I'm not immune to every iMessage problem. And the current bane of my existence is group messages — and the multiple threads they spawn in their wake.
In a perfect world, when you wanted to reach your friends, you'd start a group message and then you'd chat inside that message and only that message. Unfortunately, if your friends are switching between multiple Apple devices, using both phone numbers and email addresses for iMessage, running an older version of iOS, old Android software, or some other quirk that iMessage fails to recognize, it can cause the conversation to split into multiple threads.
The worst part of this is that those conditions I offered up above? Those are only the ones I've personally been able to test, and they're not 100 percent repeatable. You can have an SMS group with Android contacts that won't split into multiple groups. You can have an only-iMessage conversation that splits every time someone says something. Sometimes sending an image will split the conversation. It's unpredictable, and beyond that — frustrating.
Of course, when you involve our green-bubble SMS friends, or international carriers, there are bound to be quirks in the system; after all, Apple can't control how that message data is sent, only how it's received. And if, for whatever reason, a group message you send includes person A, but person A only sees this as a one-on-one conversation between you and them and responds accordingly, Apple can't really fix that.
In my testing and informal Twitter polling, newer versions of Android do appear to avoid the split bug — but I haven't had enough SMS group conversations with Android and iMessage friends to say that for sure. It may well be that group messaging might just be broken for those friends of yours on older, crankier devices.
But even if Apple can't correctly parse or control group messages with old SMS contacts in them, the company should be able to improve the user experience somewhat or at least explain to the end-user why their groups are getting split.
In fact, here's a radical idea: If the same contact has multiple iMessage IDs, or if multiple groups have the exact same contacts inside them, why not reconcile and merge them together before displaying them in the app? In other words, handle all the complexity internally, but present a simple, orderly view to the customer.
This would solve another annoying iMessage issue — accidentally carrying on two conversation windows because you've sent messages to both a user's phone number and their Apple ID. I've done this for solo users, but I also have an absurd number of group conversations between my mother, father, and sister — and every time their contacts are in a different order, it creates a new message record. It'd sure be nice to merge all those multiple conversations together.
If this issue frustrates you like it frustrates me, and you have a developer account, I suggest filing an Apple Bug Report on the subject — ours is #19814094.