If you choose a smaller than average size ring, you can be sure
there will be a smirk from the salesperson.
No, the salesperson is not expressing joy for your newfound
status. 
That only appears to those who are hard on the commission part.
I just to work in jewellery sales line but I do not do that. I
would recommend nicer ones in the same price range that the
customer is looking at... like a 4 claw look bigger than a 3 claw
ring.