"I have the true feeling of myself only when I am unbearably unhappy."

"A First Sign of the Beginning of Understanding is the Wish to Die."

"The truth is always an abyss. One must — as in a swimming pool — dare to dive from the quivering springboard of trivial everyday experience and sink into the depths, in order to later rise again — laughing and fighting for breath — to the now doubly illuminated surface of things.” 

"Love is, that you are the knife which I plunge into myself."

-- Franz Kafka

(First on my list when I start of with German literature)