I interpret this song as how people go out of their way to ensure that the ones they love are satisfied ('she knows to boil the kettle when you hum bars from grease'), but being taken for granted. The second verse in particular appears like the character is being controlled ('he brings with him a Mars bar // SHE will not buy Nestle') - it's not his choice that his lover doesn't buy Nestle. Therefore I think that this song epitomises the good deeds done by people around us and how humdrum they have become to us. The last line also evokes the idea of it being a cycle, so it's starting again.
