We don’t really learn anything properly until there is a problem, until we are in pain, until something fails to go as we had hoped.

A little insomnia is not without its value in making us appreciate sleep, in throwing a ray of light upon that darkness. An unfailing memory is not a very powerful incentive to study the phenomena of memory.

There is no man, however wise, who has not at some period of his youth said things, or even lived in a way which was so unpleasant to him in later life that he would gladly, if he could, expunge it from his memory. But he shouldn’t regret this entirely, because he cannot be certain that he has indeed become a wise man – so far as any of us can be wise – unless he has passed through all the fatuous or unwholesome incarnations by which that ultimate stage must be reached.