So I was having an argument with myself awhile back over whether some songs could be considered "deep" or not, and I couldn't really come up with a good answer. Is something "deep" if it talks about emotions? Or if it has a layered meaning? Or is it even describable? And the truth is, I don't know. I can't know. At least not in a way that I can argue with someone why *this* is "deep" while *that* isn't. I'm just going to have to be subjective. So, I want your opinion.
What would you consider to be "deep"?
EDIT: I'm asking for your opinion in general, not just songs.