"Finally, friends don’t count as respondents. By some quirk in the human psyche we would rather see our friends waste their time and money, rather than to tell them the truth!"
Your friends hate to see you disillusioned, so they let you perpetuate the self-illusion that what you're proposing in your project will work.
You best friends are the ones who disillusion you.
The policy I have been following for my new start-up is to not proactively tell friends. Instead I'd rather they tell me "omg I hear that's your website!". More of those I get, more it validates my idea and marketing. This works especially well at a uni environment and for my startup which is very super focused on my uni.