For me, this was a month or two ago. I don't remember exactly now, but my friend and I tried to verify each other, but one of us quit the device verification (with the five emojis) half-way through and uninstalled the app, so now there is a half-verified device that we can never remove. My icon with him always shows up red because of this device, and there's nothing we can do.
UPDATE: I just checked now, there's a "manually verify by text" option, I clicked "verify" and that device finally turned green, so at least now there's a way to fix this.
One major source of confusion for me is that one-on-one chats and multi-user rooms are different, but one-on-one chats seem to be multi-user rooms with just two people in them? That is confusing to me, because I see "people" and I see "rooms" but apparently people are rooms too.
All that having been said, I am very pleasantly surprised by the overall experience, and especially the pace at which it seems to improve. I use Element semi-regularly with a friend and it's been working okay. Hopefully all these kinks will be ironed out, because I really really want a better IRC, and Gitter has become infinitely better now that I can just use Element to access it.
> At the moment the vast majority of negative feedback on HN has been "it sucked" without giving a hint of what actually went wrong.
Also, I don't think that's what the majority of users are saying (and I certainly never said and don't think Matrix sucks). I'm saying "this is not good enough yet that my parents could use it", which is an extremely high bar, and I think that's the way you should take the feedback.