Oh how I used to love maths

For precisely these reasons:
http://opinionator.blogs.nytimes.com/2010/04/04/take-it-to-the-limit/?src=me&ref=homepage

The problem is with age, is that you completely forget the things that you used to find exciting and fascinating when you were younger, because you just assume that you know them. And even if you now have an imperfect knowledge of them, you just assume that it is because you can't really remember them properly. But because it seems like a step backwards to go and relearn them again, you're happy with your imperfect memory of them, mainly because the bulk of your learning is set, your philosophies and priorities are somehow set, and you don't really want to go back and rethink everything. Mainly because it's a massive drag and has no practical application to your life - just as you expected most of school was when you were there.
I don't think I really miss those days when I was young and ignorant of learning, I just wish that I wasn't constantly reminded of how in the world I have no complete knowledge of, and especially how it's a constant Sisyphean task trying to know everything about the world. Even if most of that knowledge may be abstract and wholly impractical, it's real in some way, and it's a shame that with every avenue I venture through and recognise, there is a new, wider avenue that opens up at its end.
I remember once being told that Beethoven, on his deathbed, said something in the sense of the fact that he feels as only he has only begun to understand the world and there is still so much he hasn't yet mastered. And then there are the rest of us, who have to live in the knowledge that if Ludwig so moaned, we really aren't trying hard enough or seem to be content with too little.