I can't help but giggle like a stupid fangirl when either Shaun helps Desmond with the Truth videos, or they have a conversation. They're just so dorky, and Desmond actually seems totally interested in what Shaun has to say, especially in Brotherhood(I would exit the at everyone beginning of a new sequence, just to watch Desmond and Shaun talk).

So I want me some Shaun and Desmond geeking out on some history, or talking about one of the glyphs/clusters that they solved, and geeking out even more on that. If you want, you can have them realize that they are perfect for each other and hook up. Hell, they can have sex if you want :D