I've had very similar experiences with diamond jewelry stores. For my five year anniversary my husband took me to pick out a diamond anniversary ring. Well,I am never going back to a jewelery store again!!!! I think I'd rather shop online, buy a loose diamond and just have it set by a custom designer. Needless to say, I felt like I was totally talked down to and made to feel like I was wasting their time if I didn't buy a ring right there and then. Plus, the fact that I'm a woman and I was asking all of the budget questions and technical questions for some reason was weird for them. I don't know what the experience was like for my husband when he was buying me my engagement ring, but I imagine they were a bit more patient and polite.
Anyway, It's a good thing that I went well prepared with lots of questions, because otherwise, I think they were really trying to scam me and keep information from me as much as possible.
In the end of things, I had my husband buy me an antique cocktail ring at an auction. It's absolutely gorgeous. As soon as I get my digital camera fixed, I'll post a picture!