One of my favourite things about Don McGlashan's songwriting (and there are many) is this - the choice he makes about the perspective, or point of view, of the characters in a song.
Harbour Bridge is a perfect example - it's a song about parting, about breaking up with someone you love; but the person singing it manages to pin all their problems on the various failings of...the bridge they're driving across.
If only bridge weren't so grey / long / high / convenient, he'd have been able to think of, and say, everything he wanted to tell her; and, maybe, she'd have stayed...