Truth is stranger than fiction, but it is because Fiction is obliged to stick to possibilities; Truth isn't.
— Mark Twain

Sir, I have found you an argument. I am not obliged to find you an understanding.
— Samuel Johnson

Activate yourself to duty by remembering your position, who you are, and what you have obliged yourself to be.
— Thomas Kempis

My misfortune is doubly painful to me because it will result in my being misunderstood. For me there can be no recreation in the company of others, no intelligent conversation, no exchange of information with peers; only the most pressing needs can make me venture into society. I am obliged to live like an outcast.
— Ludwig van Beethoven

The beggar is the only person in the universe not obliged to study appearance.
— Charles Lamb