Recently, I had two similar conversations with two similar people that ended up with very different outcomes. Both conversations started the same way: I brought up an idea I had that I wanted feedback on. In both cases I was talking with people smarter then me who had experience I thought would shed light on the idea I was trying to refine. After I explained the basic idea, both people thought the same thing: "that is going to be really really really hard to make work". But the end result of the conversations were very different. In one case, the conversation lasted about 10 minutes and then the subject was courteously changed to something else. In the other case, the conversation turned into an hour+ discussion about the idea full of new insights, new potential, and eventually a significant improvement on the original idea.
Why were the outcomes so different if the initial response from folks I was talking to was so similar? Because the first person said no and the other person said yes but meant no and that approach made all the difference.