We all have things we’re embarrassed to have only learned recently. Pronunciation of a word, an easier way to do something, etc.
This is about when that new fact is so closely related to something you already know/use, you’re extra pissed you didn’t find it out sooner. The new stuff is just as valuable as the old, yet it still took you forever to discover it.
I’m just now finding out that on youtube, you can do the special google tricks (like the “or” pipe, intitle:, or double quotes around exact phrases) when searching through uploads on a particular channel.
However, I’ve known you can do that stuff for a regular youtube search since google bought them out.
For another path, you can talk about things you’re supposed to know (for whatever reason), but don’t. Like a middle school math teacher who slips up on the order of operations, or something.