I think you're both right. I've always thought this song was about meeting and working with Elvis Costello--I mean, the song could be applied to any situation where, as user1951 put it, you idolized someone only to realize they didn't really deserve it for one reason or another. I think the basic plot of the song is that the narrator got to be around/work with someone she really admired, only to be cast aside (the eggshells I've been treading couldn't spare me a beheading...from a Caesar who was only slumming) for being beneath him or for not idolizing him enough...something like that. But plot aside, I think it's just about disappointment in someone you used to admire.
I think you're both right. I've always thought this song was about meeting and working with Elvis Costello--I mean, the song could be applied to any situation where, as user1951 put it, you idolized someone only to realize they didn't really deserve it for one reason or another. I think the basic plot of the song is that the narrator got to be around/work with someone she really admired, only to be cast aside (the eggshells I've been treading couldn't spare me a beheading...from a Caesar who was only slumming) for being beneath him or for not idolizing him enough...something like that. But plot aside, I think it's just about disappointment in someone you used to admire.