"Whose fault is it, if not mine?"
There is no definite answer to that question. Probably it had to happen. But that would be a harsh thing to say in front of her.
Even though I tell Sonia that it is foolish of her to blame herself - she didn't know that her sulking a bit, which is not rare of her, could lead to something so unexpected - yet, speaking frankly, I understand her position. I myself am not left untouched by traces of guilt. After all, it was my birthday treat when it all started.