The word 'regret',
you only use it when its too late to change things.
You still have a chance to change things, don't you?
- Mineta Toru (Chisato's father) to Chisato
I know Chisato's father is a worthless father in the drama, and such words coming from such a man is not something I would take seriously. But then, erase the worthless character, the quote becomes meaningful, don't you think?