There are tons of quotes I like. Below are some of my favorites.

The man who lies to himself and listens to his own lie comes to such a pass that he cannot distinguish the truth within him, or around him, and so loses all respect for himself and for others. And having no respect he ceases to love, and in order to occupy and distract himself without love he gives way to passions and coarse pleasures, and sinks to bestiality in his vices, all from continual lying to other men and to himself. - The Brothers Karamazov (book) by Fyodor Dostoyevsky

I don't want to live someone else's idea of how to live. Don't ask me to do that. I don't want to find out one day that I'm at the end of someone else's life. - Out of Africa (movie) by Sydney Pollack

Someone once told me the definition of hell; on your last day on earth, the person you could have become will meet the person you became. - Anonymous