"There is much sadness in knowledge."

I don't know if I agree with that, but I also think that there is much bliss in wisdom.

And regarding one of the points you made. Everybody wants to change the world. There is a Spartan quote. When Agesilaus was asked how far the bounds of Sparta extended, he replied by showing his spear and saying "as far as this can reach."

I think he is right.

How far does that which you call the world extend? As far as your hands can reach. No further. And that's a world you can definitely change.