That there's so many books to read, albums to listen to, films to watch, information & knowledge to learn, so many fields you'll never become an expert in.
That we live, tops a 100 years. And in that 100 years, we won't even get a grasp on the scale of human knowledge and creation. I generally read more, listen more & watch more than the majority of people in the world (i'm not being arrogant here, i'm just saying that I, you know. It'll be the same for the majority of dis'ers) but yet I still won't ever be able to come close to knowing and watching and listening and reading to everything.
By the way, I know this is the wrong time to post it. Hometime on a friday.