There's only one corner of the universe you can be certain of improving, and that's your own self.
Nature never deceives us; it is we who deceive ourselves.
I wanted to change the world. But I have found that the only thing one can be sure of changing is oneself.
Don't bother just to be better than your contemporaries or predecessors. Try to be better than yourself.
If you want a thing done well, do it yourself.