I mean Xena notices every tiny bit of emotional change when it comes to me, she can dictate when I'm angry or in a sad mood - then she will be all over me trying to play with me to brighten me up - how lovely she is.

Yes this happens with me too. I have noticed whenever I am sad or upset, my cat would just come to me and sit next by me, make me pat and love her to keep me busy. Isn't that cute.