As soon as you get into something new, you discover how little you know, or how bad you are. Some people deal with this by building up their achievements, and telling anyone who will listen how good they are. People like me start out all excited, then realise that we know nothing. I've always wanted to find out how good I am - especially in sporting terms. When playing rugby, I kept going until I found a club where I had to really work to hold down a first team place. In business, if someone asks me about a field, I can talk about it for a while, but will then point them at someone who knows more. Now I'm running what my mother thinks is a lot, I know that there are plenty who would consider my weekly mileage a nice morning warm up.
I guess that's the thing: there is always someone better. I tend to under-value anything that comes easily, or that I've forgotten how hard I worked for, especially when I know how much I don't know. The corollary is to try not to over value anything that currently seems impresive because I'm finding it hard. Ignorance is bliss, and in the right head, expertise. Beware the novice who thinks he's cracked it.