My favorite, though more of a UI blunder than a bug, and I think fixed now: If you right clicked on a user name and hit “Add Note”, a box would pop up for you to type in. Like for writing your note in. But that box was in fact the “send them a direct message” box.
So if you hypothetically wanted to write “Asshole” as a note, and didn’t pay attention to what text box had focus, well, that was a bad time.
I think a lot of people are kind of bad at written communication. It’s not an easy skill.
Often at work folks will write twice as many words and clauses as needed. The Hemingway editor ( https://hemingwayapp.com/ ) isn’t perfect, but I recommend they take a look at it.