Yep, I relate to it quite strongly. While I tend to be optimistic and trust people until proven otherwise, I still will analyze other's motives, especially if the person's actions strike me as odd or out of the ordinary. I'm usually dead on when it comes to figuring them out and consider this ability to be a good thing. So, I'd describe myself as quietly cynical and fairly sceptical, and not at all gullible.
This trait has also gotten much stronger with age which is of course true with the teriariy functions.