Maybe I just look into things too much, bit I alwaysss catch Kaidan and Liara giving eachother these miffed looks as if to say "bitch, she's mine", in the middle of cutscenes! Like I'll be talking innocently to some third-party character, and I'll catch Liara giving Kaidan this "blerghh" look behind my back or vice-versa.
It always cracks me up XD
But this scene is actually totally on purpose, since I accidentally *spoilers* let Liara on unwittingly ALONG with Kaidan who I was actually trying to get.
Needless to say, "things" went downnnn.