If you aren't mentioning your idea or that you are working on something, what is the subject of the call? I think I'm not understanding how a cold call like this would work.
1) they want to appease me, especially if they're family or friends 2) they like the idea in their minds but that may not be exactly what you have in mind 3) their idea is the same as in your mind, but they don't have the propensity to buy.
You want to listen to what their true needs are instead of shoehorning your product into their problem. You want to build the product from the ground up so to speak. Sometimes, you guess their needs completely right and your product is exactly what they're looking for. However, this is extremely rare because the odds that ex nihilo you got something that fits their needs exactly is 1/infinity. This does not mean that you cannot tweak your existing product to fit their needs, but it is simply better for both you (no prior sunk cost) and the customer (can get something that actually solves their problems) in the long term.
I think I'm still not understanding how you are making a cold call, over the phone, to a complete stranger, and somehow getting them to start talking about problems they may have without there being a purpose (from their point of view) to why they're talking to you in the first place.