The longer you've been in the computer programming racket, the more you realize your knowledge is but a fraction of what's available to be known. I've been doing this for pay for 28 years (and before that without): There's lots of stuff that is terra incognita to me. I never knew some of that existed, or only just had a dim idea of it. Just keep learning, it's what makes the field so fascinating. It's like an onion - everytime you peel back a layer, you find another layer underneath (and then you cry).