One of the things that I didn't understand after the finale was why would Agatha be afraid of seeing her son again after centuries of mourning and missing him?
And after thinking about it I realized that is obvious that she is afraid of facing Nicholas (and Rio too), cause facing him would mean that she had to admit that she was wrong, that after all these years her son was protected and taken care by Rio in her realm. Seeing her son and the love of her life fine and happy with each other would make her realize that she spent all those centuries fighting and hating the woman that she always loved for nothing, that she spent her life building these barriers to tried to keep her feelings away (which she failed miserably) with the only reason that she took their son (when in reality, Death broke the rules and gave her the thing that the mayority of people don't have and that's time, Rio gave her seven years to say goodbye to Nicholas) but still Agatha was too hurt to see through her own pain.
That's why she is afraid of seeing her son again because it would mean that she could have spent those years with the love of her life instead of hating her and feeling guilty that she couldn't stop loving her even after taking their son; Agatha knows deep down that Rio was right, did her job and that their son is in good hands, but knowing that you could have live a better and happier life would be too painful to admit
