From a very interesting short interview with a Dominican monk.
The most attractive thing on the planet is a person filled with gladness. The modern world doesn’t know how to take this; it’s so completely rare. When they meet someone who is filled with gladness, their first reaction is suspicion. Are they insane? On drugs? Or have they met someone astonishing? When the world meets somebody like that, the world can’t help but ask how you became like this because the world wants to be like this too. Everyone would rather be glad than miserable. The importance of each human being’s witness is vital, even before he or she opens their mouth. The witness of gladness is what makes the world stop and say, “You’re different, and your way of living seems better.”
Read more here.