He tells Robert that he knows how important Downton is to him, and strives to make that become better.
Telling Molesley that he really appreciates the job he does.
Never losing his patience with Mary, even though she's being very much a pain in the arse.
Reassuring Edith that, while he is not interested in her like she might like, he knows that she is bound for something a lot greater than just being a countess.
Her slowly thawing to Matthew.
Cheering on Anna after she mentions her upcoming date with Bates. Mary becomes an instant Shipper on Deck for the two of them.
Telling Anna she knows how the maid feels around John Bates - because she feels exactly the same way around Matthew.
Fixing her relationship with Edith.
After Matthew and Robert have their row, she calls out her father for how wrong he has mistreated her fiancé and chooses to join him even after her father threatens to cut her off.
Hitting it off with Michael Gregson.
Finally being recognized for her merits and actions.
Joining Mary after she calls their father out.
She becomes the biggest Matthew fan in the house.
Revealing to Matthew that she has also come from the future. Matthew is so happy he gives her The Glomp.
Telling Mary straight out that she must not blame herself for Pamuk trying to kiss her.
Helping Gwen with her plans to learn how to typewrite.
Helping Bates to get divorced so he can begin a relationship with Anna.
Covering for Thomas' sexuality with nary a thought. Then telling him - in private - that she knows he's gay, but she does not give it any importance.
Bates awkwardly proposing to Anna before the start of WWI by revealing that he bought the Grantham Arms.
Heartwarming in a meta sense too; the author based this on his father's awkward proposal to the author's mother.
General Allen Lothrop
After hearing about Matthew and Robert's falling out and how the Crawley girls have been cut off he quickly offers to let everyone stay at his massive home in London
Later he gives Mary away at her wedding since Robert isn't there
When Mary tells her that she wants to marry Matthew the next day and doesn't mind if it is a crummy little wedding Cat instead decides to throw her the best wedding she can, convincing her own minister to officiate