I've had a theory for at least 10 years now about how people can react to new ideas. Someone (usually me) comes up with a new idea and they expect one of two types of responses: Confirmation or Affirmation.
Sometimes you just want to hear someone agree with you. You haven't thought it all out, the idea is in its initial stages and you don't want someone to be a wet blanket, you just want to get it out. You need a sounding board and a chance to just listen yourself talk. You don't need the person at that moment to start finding holes in a nascent idea. This is what I call affirmation.
The other times, you've got an idea and you're ready to commit to it, but you need someone to play devil's advocate. You want them to sanity check the idea and tell you if they find anything wrong with it. You want them to poke holes in the plan so you don't do something dumb. You appreciate it when they really try to grok what you're saying and look for the problems. This is called confirmation.
Ever get into a fight with your SO or good friend because you're telling them some new idea and they give you the wrong kind of feedback? "What? I'm agreeing with you." Stop it! I want you to think dammit! "Sounds fine to me." ARRGH! Or the other side: "Will stop being a dick, I'm trying to tell you something." I'm just saying that it's not realistic... "I know it's not realistic, that's not what I'm saying... ARRGH!
Anyways, I just had a new idea and then I remembered this. My definition of a real friend? Someone who knows what kind of response you want to new ideas. I know, I'm weird.