I just read on CNN (or maybe N_8 posted it?) that some drive through operators were actually located off-site in India or something and the orders are relayed back to the resturant electronically. That's the case, it might be rude to wish them a good morning because it might be night time, or the middle of the afternoon, the next day, who knows? Tell your wife that next time she harps on you and see what she says...