Where can I see the participant list?
Shown above is a sketch of what I saw in a popular app for online meetings.
In the picture there are 4 participants visible, and in the bottom left there is a small portrait with the text “+7” overlaid, indicating there are 7 more participants in the meeting.
Now, quickly tell me, how can I get a list of all the participants?
The obvious answer to me was to try clicking the indicator that told me there are more people in the meeting. In fact it is so obvious that it must be that button (which turns out not to be a button, just an indicator) that I must have tried multiple times already.
That is simple, obvious and wrong.
The correct answer is to tap the screen once, then find the overlay menu, then click the ellipsis symbol in the overlay menu to see the overflow menu, and then you can see the participant list.
Chekhov's gun is a dramatic principle that states that
that states that every element in a story must be necessary, and irrelevant elements should be removed. Elements should not appear to make “false promises” by never coming into play.
This holds true for ui elements as well: If a button doesn't do anything but is only for decoration it probably shouldn't be a button. In this case however it would probably be better to fix the button so it works, I have missed it a number of times already.
I've previously written that Perfect UX is impossible, and I stand by those words, but that doesn't mean we cannot do a whole lot better than we do today.
BTW: Excalidraw is awesome as far as I can see, it is also free/open source software so you can self host it if you want.
Edit 2020-05-06: Add reference to Chekhov's gun