A live unexamined isn't worth living. I will add, "A life unlived isn't worth examining.

The secret of life is in art.

The gods have been good to you. But what the gods give they quickly take away. You have only a few years in which to live really, perfectly, and fully. When your youth goes, your beauty will go with it, and then you will suddenly discover that there are no triumphs left for you, or have to content yourself with those mean triumphs that the memory of your past will make more bitter than defeats. Every month as it wanes bring you nearer to something dreadful. Time is jealous of you, and wars against your lilies and your roses.

When both a speaker and an audience are confused, the speech is profound.

And now, I am dying beyond my means. (Said while sipping champagne on his deathbed.)

We have really everything in common with America nowadays, except, of course, language.

The modern sympathy with invalids is morbid. Illness of any kind is hardly a thing to be encouraged in others.