I never really understood people getting annoyed with the "love" subplot, which is barely a subplot to begin with. It's a throwaway conversation of a person trying to rationalize her desire to see the person she's madly in love with, and echoes Cooper's own struggles. It's not at the heart of the film nor does it eventually influence their decision, but it's also one of the underlying themes running through the film of reason vs emotion, and scientists challenging their conceptions as they venture into unknown territories (both figuratively and literally). It's not my favourite scene of the film in any case, but I find it a bit of a strange that it could have spoiled the film for many people.