What about Rosie, then? Sam certainly wanted
her, whether he explicitly stated that or not.
I don't think that Sam's secret is lack of ambition, I think his secret is his ability to keep his priorities straight, never forget his principles, and remain humble throughout. And I don't think that humility equals lack of ambition. It equals lack of
selfish ambition, that's for sure. There's a difference between the two.
But you are absolutely right in the sense that it seems as if the Ring zeroes in on the subject's inherent weakness (such as selfish ambition) and works to magnify it.