I have a few.
Daenerys poker face when negotiating with the slave trader. His face when he realised that she understood everything he said.
Robin the breastfed near adolescent. I like that he wanted to see Tyrion fly out of the moon door. I loved that when Littlefinger handed him as gift he accepted exuberantly before chucking it out the moon door.
Tyrion introducing himself to the dragons and them warming to him.
Cersei's revenge against everyone who wronged her. The Sept of baelor blowing up and her fulfilling her promise to kill Septor Unella.
When we see what happened to Hodor. 
Also "Tell Cersei. I want her to know it was me". 