I always saw Sweet Nothing as a cute song, because of the "outside they're pushing shoving" before the "You're in the kitchen humming, All that you ever wanted from me was sweet nothing".
I interpreted it as people are always wanting more from her, but he just accepted her and she could be herself, and can admit to him that she's "too soft for all of it".
Eta: I think without some of the other lines in the song, the "All that you ever wanted from me was sweet nothing" could be a negative thing, but with the rest of the song it kinda makes it a positive. Just my interpretation anyway - it's interesting how it can mean different things to different people!