Personally I think it's plane-simple common courtesy to say hello and good bye to anyone when you enter their office/room/house. Anyone that believes they are better because they are a capt or that as an FO you deserve none until you upgrade needs to realize that honestly you are only a pilot, plane and simple not anything more or better than the guy in the right seat only more experienced, hopefully
I always make it a point to say hello with a handshake and name exchange with both crew members when I jumpseat. It's plane and simple etiquette.