You really do have to watch the entire set of scenes. They're adorably awkward (a theme for this particular challenge, actually, which you'll see when you read the BroShep choice next), and Shepard obviously has the more level-headed approach to the whole scenario. She's the one who proposes it, and she even gives Garrus the choice to decline (the idea of consent is such an important issue for me).
"So ... your, uh, hair looks good, and your waist is ... very supportive."
But I didn't realize how invested I was in this relationship until I got to Mass Effect 3. When Garrus showed up on Menae, I bounced excitedly with this silly little grin on my face. I wanted to see them reunited because they are just so good with each other. They respect each other's abilities, both on and off the battlefield, and at the same time can be playful and/or tender when the situation calls for it. Her position as a commander in the fleet, of course, isn't as much of an issue as it was before, since he's saluted by turian generals now, but he still recognizes her rank and follows her orders, while providing tactical (and personal) advice. Again, here is a collection of the videos from the main game to give you a better idea of what I'm talking about.
"Forgive the insubordination, but your boyfriend has an order for you: come back alive."
Their relationship just seemed so real to me. When the Citadel DLC came out, I was so damn excited when I found out they'd done extra scenes with Shep's love interest, and Bioware did not disappoint:
"Shepard, is it just the alcohol, or do you have vids running in your head of us mostly naked, completely alone, and shamelessly rolling all over a couch?"
Is it silly? Sure. Is it fan service? Undoubtedly. But I loved every minute of it. It's like the developers read my mind when they asked the question, "What do Shepard and Garrus do on their off time? You know, when they're not sexing it up, interspecies-style." Their banter, their obvious closeness, their sincere friendship that backs everything else up ... it's just perfect.