There is an excellent post from Stumbling and Mumbling on this issue, it can be found here. I love the conclusion:
Now, I don’t want to claim that all of this year’s most popular songs contain howling irrationalities. The mighty Lady Gaga passes muster. But could it be that such irrationalities – as distinct from plain nonsense – are more common now than years ago? If so, isn’t this yet more evidence of the decline of civilization? And what hope is there of people becoming properly educated if they are exposed to such cognitive errors? Will no-one think of the children?
In the comments someone suggests that the lyrics of the Beatles were more rational, and that the rationality of pop singers is declining over time. However, I’m not convinced that is the case.
For example, in the the “The End” Paul states (and John heartily agreed with) that “the love you take is equal to the love you make”. Now this is true on average, but I doubt there is any behavioural rule that ensures this occurs for every person. Such a rule could lead to people “over-investing” in love, in the belief that any they give will be returned to them.