I think that this song is definently about a relationship. The workin, ect, ect, part is just wanting to be with your bf/gf. Now, i think that it is about a relationship where they don't hide anything or keep secrets, thus an "ideal" relationship. "Never said it was sunshine, but you took it all the time" is saying that the truth isn't allways good (sunshine = good!) but you took it anyways. Then the next part is just showing how good it accually feels to be truthful with your gf/bf.
I think that this song is definently about a relationship. The workin, ect, ect, part is just wanting to be with your bf/gf. Now, i think that it is about a relationship where they don't hide anything or keep secrets, thus an "ideal" relationship. "Never said it was sunshine, but you took it all the time" is saying that the truth isn't allways good (sunshine = good!) but you took it anyways. Then the next part is just showing how good it accually feels to be truthful with your gf/bf.