Some of my favourite moments are when Maestor Pycelle trolls people - during the council meeting in the last episode where he 'accidentally' drops the message on the floor when handing it to Tyrion. Just for his private spite. Ofcourse, later follows it up with the "Tyrion was rude and should apologise immediately bla bla bla". This guy doesn't serve the realm and the last person you'd want to have giving you medicine.
Also some fun conversations from Season 1: Lord Varys talking to the [King?] of Braavos in the dungeons of Kings Landing, about having to bide their time (since war seemed inevitable thanks largely to Little Finger and the ineptitude of the Starks lest we forget). Was such an odd moment, perhaps entirely a plot device to keep Varys quiet about Little Fingers game playing at the time, or perhaps just an old reminder that he has his own unknown grand scheme for the realm. Power comes with armies - Braavos probably does not hold an army so I doubt there can be very much direct influence he can cause with them.
We'll probably see more of that city (it featured early on with the hiding spot for both Viserys & Daenerys Targaryen), I have to assume that the sword master never died in a 1v1 with a broken stick after knocking out 5 guards with a wooden sword, so he'll probably be around to lend a hand - and finally the guild of the faceless for Arya to join. And lastly it'll probably be the last travelling spot for Daenerys before travelling across the sea to fuck shit up.