It is good to mature and grow with time but not necessarily good to stop believeing that you can change the world. One of my favourite quotes is from Gandhi who said, "you start by being the change you want to see in the world".
(thanks to flickr and dan taylor for sharing the image)
Returning to reality, I am a fan of Kathy Sierra and I higly recommend reading both these posts from her. Read it, chew on it, distill it and then see if you can apply it.
And remember, it's almost never about making them more of an expert on your tool, it's about helping them get really good at whatever it is they do with your tool. Nikon's tutorials aren't about making camera experts, they're making photography experts.
So... it's time to let that go. You're not keeping up. I'm not keeping up. And neither is anyone else. At least not in everything. Sure, you'll find the guy who is absolutely cutting-edge up to date on some technology, software upgrade, language beta, whatever. But when you start feeling inferior about it, just think to yourself, "Yeah, but I bet he thinks Weezer is still a cool new band..."
I try not to just plug other posts with no purpose but these are well worth your time. Trust me.