Okay, same thing like SG-A but for the other series. Can`t be tha difficult

This is the quote:

A: You've got that look.
B: To which look are you refering, ...?
C: The one that says I have misgivings about this mission but deep down I know we're doing the right thing?
A: No, the other one.
C: Oh.

Who are A,B and C and which episode in which season? Names replayed by dots :-)