Well I know that in Corra they use it for effect in poignant scenes; for example when Richard Hillman tried to kill himself, Gail, David and Sarah by driving into the canal, the music on the car radio was "You and me always" by the Wannadies, and for the scene when Roy led Hayley into the bedroom for their first ever night of lurrve the background music was "You make me feel like a natural woman!"
There are other examples (which I can't remember at the moment) but it seems that someone working on the set has a wicked sense of humour matching songs to the scenes.