The further you get in a girl's side story, the higher chance she does something at certain points in your day. For instance, you might come to work and see that Jade left you a latte and a cookie at the security desk. Wither might catch you at your lunchtime to give you a quick kiss and send you on your way.
I know a lot has been said but this bit stole the show for me. I love this idea, I can't help but think of all the possible interactions. I now also kind of want other titles to have a similar system just because of how much potential I think it has