Now, This Is Wierd

I have never quite gotten the point when my wife checks the expiration date on sour cream. I mean, I don't really get using cream that has gone bad in the first place, but worrying about its "use by" date seems just misplaced to me. But this weekend I caught her actually removing the lid and smelling it to see if it was okay. Smelling it. Lady, it's freaking sour cream; it smells bad when it's good, what does it smell like when it goes bad?

Well, by definition it doesn't "go bad," it is bad, but...