YouTube constantly prompts me to update to use a real name (and thus attach a Google+ account to my email address). I've selected the option to continue using my old username only, but it doesn't matter — it just prompts me again later over and over. Is there any way to permanently disable this, or a userscript to prevent it from popping up? I use Chrome if it matters.
Check out this userscript:
Removes the pop-up from Youtube that tells you to "Get a better name on YouTube" by using your Google+ username instead.
I got the same prompt to get a better username from YouTube. I followed the prompt, and told YouTube that I wanted to keep my existing YouTube username. This was a one-shot deal for me. I haven't received the same prompt from YouTube again.
So why doesn't this work for you? I was already logged in to YouTube at the time I received the prompt. Maybe YouTube doesn't save your settings unless you are logged in when you input them.
The language used in the steps that follow the YouTube prompt is tricky, and may even be confusing to some people. I strongly advise you to read everything very carefully before you click on anything.