Life should be an aim unto itself, a purpose unto itself. - Michel de Montaigne

And in this we must for the most part entertain ourselves with ourselves, and so privately that no exotic knowledge or communication be admitted there; there to laugh and to talk, as if without wife, children, goods, train, or attendance, to the end that when it shall so fall out that we must lose any or all of these, it may be no new thing to be without them. We have a mind pliable in itself; that will be company; that has wherewithal to attack and to defend, to receive and to give: let us not then fear in this solitude to languish under an uncomfortable vacuity.

The most certain sign of wisdom is cheerfulness.

[I]n my country, when they would say a man has no sense, they say, such an one has no memory; and when I complain of the defect of mine, they do not believe me, and reprove me, as though I accused myself for a fool: not discerning the difference betwixt memory and understanding, which is to make matters still worse for me. But they do me wrong; for experience, rather, daily shows us, on the contrary, that a strong memory is commonly coupled with infirm judgment.