A colleague who met me strolling rather aimlessly in the beautiful streets of Copenhagen said to me in a friendly manner, "You look very unhappy"; whereupon I answered fiercely, "How can one look happy when he is thinking about the anomalous Zeeman effect?".
Wolfgang Pauli, Charles Paul Enz, K. v Meyenn (1988). “Wolfgang Pauli: das Gewissen der Physik”