Garrus had a limited amount of conversations aboard the Normandy, but he still came off as one of the liveliest of the characters. He really changed over the course of ME1 and became a much more dynamic character in ME2. In ME1, while he acted foolhardy at times he was very submissive and polite to Shepard, always following commands. The relationship between Shepard and Garrus really came off as a student-mentor sort, Garrus learning what he can from Shepard. By the sequel however, Garrus has taken it upon himself to do what he believess right and has gained much more flare as a character.
It was his line: "Damn that hurts, my face is barely holding together as it is. It's just as well, everyone was always ignoring you and hitting on me. At least now this gives you a fair shot."
That line really showed me how much of a "bro" Garrus has become to Shepard. He really comes off as the right-hand man, the old buddy character, and they did a good job with it. I really do feel like in-game Garrus and Shepard have a bromance going on.