I ran into a scenario recently where this test failed:
[Test]
public void You_have_to_be_kidding_me()
{
string a = "You have to be kidding me ";
string b = "You have to be kidding me ";
a.ShouldEqual(b);
}
It took me quite a while to determine the problem, as it originally came from a column in the database with natural keys.
When a test like this fails, it's time to call it a day. Any guesses as to the problem?