Chinese Mind Tricks

There's one aspect of Chinese culture that continues to amuse and, at times, frustrate me. It's what I like to call the Chinese Mind Trick. It happens when you ask someone for something, but rather than provide it, they try to convince you that you don't want it. It looks something like this:

Me: Do you have this dress in a smaller size?
Vendor: This is a good size for you.
Me: No, it's too big. Do you have a smaller size?
Vendor: A smaller size wouldn't look good. You should get this one.

or this:

Erik to vet: Can you tell us where we can get our dog a haircut?
Vet: This kind of dog shouldn't get its hair cut.

It's really hard to know how to respond to these interactions. Usually we get into them because people are unable to provide the information or products we want, but don't want to admit it because they would lose face. I understand that, but it would be so refreshing if someone would just say, "no" or "I don't know" in response to our questions.

It's a good thing I'm not looking for any droids, cause I think I know the answer I would get.