I don't think Matt Czuchry has just one expression. On contrary I think he's always really good even when they gave him no lines at all and just put him in the background. His acting is not showy, really subtle and never forced. And even the character is not one-dimensional at all. But it's hard to show all you range…

"Seeing everyone wake up in bed was interesting. But why didn't see Cary?"
Because those writers don't really give a damn about Cary's character for se. They just love to use him to give other players more to do and most of the time they fail to give him what they're giving to Diane and Will: his own big personal…