After all, someone who seems to be trying to make herself look shorter than she really is all the time like Elly is doesn't seem to realize that she's clearly sending the subconscious message "I am not worthy to look in your eyes, Big Strong Alpha Male." Elly might talk about how the revolution is sputtering but she's not helping her cause by constantly trying to prove that she isn't trying to upstage John.
That being said, this need to not 'embarrass' the man by being almost as tall as he is might explain Lynn's love for depicting the male characters as being twice their wives' size, it and exhaustion don't tell the whole story. This is because a person who is ducking all the time is also subconsciously trying to protect herself from an imagined attack. Remember how she thought John was going to beat her up because she dinged his sports car? It seems to me that for some unknown reason, Elly has an exaggerated and unrealistic fear of getting her ass kicked for not much of a reason; thus, she's trying to protect her vital parts from phantoms and delusions.