Justice Sonia Sotomayor says: "the problem with every test is that you can find an exception that makes the application ridiculous."

Doesn't that just make you want to think of a rule that does not require an exception to avoid ridiculousness? Then aren't you intrigued by the paradox that you will have just come up with an exception to her rule (about the need for exceptions to avoid ridiculousness), and that will simultaneously support and undercut her rule?

Or you can just think about whether there should be a clear test for determining a corporation's "principal place of business" for the purposes of §1332 diversity jurisdiction or whether it would be better to use a multi-factor approach?