9-
You're smile, it makes him feel instantly better after a hard day and can bring a smile onto the sarcastic time lords face too
10-
Your laugh/voice, whenever he is sad he tends to sit in a miserable state for hours upon end until he hears you laugh. It could be anywhere, a party for example and all he needs to do is listen for you and your voice and it instantly make him happier
11-
Your sarcasm, he loves how you'll sass aliens when they're being 'rude' even though sometimes it gets you's in trouble he just loves how you'll fight and get snarky in the face of danger
12-
Your intelligence, it amazes him how easily you figures things out and no matter what he's on about you always understand. Although sometimes it can get quite competitive between the two of you when you decide you're the 'genius' in the ship