"No, it was not superstition, it was a sense of beauty that cured her of her depression and imbued her with a new will to live. The birds of fortuity had alighted once more on her shoulders." -The Unbearable Lightness of Being by Milan Kundera

Tereza felt "called by all these fortuities (the book, Beethoven, the number six, the yellow park bench)" to seek Tomas. "It gave her courage leave home and change her fate." This is how she determined her destiny to Tomas. I do like the idea of chance. When it's not forced, so you feel like maybe it was just meant to be. The more bizarre the coincidence the better. The author also points out that there are numerous coincidences everyday in our lives but we do not recognize most of them. I guess it is one's choice to give meaning and beauty to coincidences from the one's past, the values one hold, etc. Also notice how once Tereza recognized these fortuities, she gained courage to let them guide her actions.