Unhelpful error messages
Alex Chan on unhelpful software error messages:
Good error messages explain what’s gone wrong, and give clear steps for how to fix the issue. [...] If you write software, you need to learn to write good error messages. Practice explaining things. Talk to your users. Find out what their mental model of your software is, and how they describe it. Write your user-facing text in their terms, not yours. It’s hard, but it’s skill you can learn – and it pays dividends in the usability of your software.
I'm reminded of Destiny 2's error code system. If you're ever booted from the game, it will display an (often generic) error message alongside an error code. Sometimes the error copy will identify the issue there and then, but to figure out a solution, you have to head to Bungie's support website and look up the provided error code. That's not the end of the world, but the documentation can be pretty light on detail which makes troubleshooting errors a challenge:
No specific criticism intended toward Destiny— this is just the first example that came to mind; plenty of games could stand to follow Alex's advice.