"Do what you love"

I've heard that phrase many times; it's decent advice. But I've also heard that people shouldn't identify too closely with their jobs.

I wonder what people should do when they don't particularly "love" anything specific. Should I not apply for a marketing job because I don't particularly love marketing?

I modified the original Dilbert comic (June 28, 2007) a bit to fit my blog's format and my personality a bit better.

Mr. Adams, please don't sue me.